RAM,go to ->
ftp://ftp.diamondmm.com/pub/display/viper/viper_v770/ and get the 4.01 drivers if your CD doesn`t have them,I`ve tested most drivers for the TNT2 and got best performance from the 4.01 drivers. Follow the below instructions (bold text) and it should clear up the problems your having-it sounds like a registry problem to me.
Recommended BIOS settings for TNT/TNT2
You'll need to restart your computer, and hit either Delete or F10 (or the key that is denoted on your screen) to enter your BIOS setup. If you've never seen your BIOS before, take a moment to explore it (not changing anything) before continuing. This will help you become familiar with changing the settings discussed herein. Some BIOSes may not let you change some of the following options, but if you'd like to be able to play with them anyway, using the program TweakBIOS will serve you well. Unfortunately, the program will not save your settings for you unless you buy the program. Therefore, you'll have to reapply them every time you restart.
Generally, if you have no major problems, these settings should be fine. But if you run into problems, adjusting these BIOS settings may help you. It is recommended that you adjust only a few settings at a time, rather than all of them at once. (Write down the original value for any settings you change first!)
These are the settings that NVIDIA and Tweak3D recommend:
Assign IRQ to VGA (or video) - Enabled or set to "Auto". The TNT and TNT2 require an IRQ to operate.
Video BIOS cacheable - Disabled or default. This shouldn't cause problems but won't significantly boost performance.
Video BIOS shadow - Enabled. This will speed up VGA BIOS accesses (like DOS dir, etc). Disable if you experience problems.
VGA Palette Snoop - Disabled. This is an old feature that is not required by the TNT/TNT2.
PCI Palette Snoop - Disabled. This is somewhat like the feature above. It should not be enabled for the TNT/TNT2.
C8xxxx-CBxxxx Shadow (where xxxx is any hex #) - Disabled. The TNT and TNT2 are already shadowed. These can be enabled if no other hardware tries to shadow in this area.
AGP Aperture size - If your TNT is of the PCI variety, this won't affect you, so jump ahead. The AGP Aperture size is the total amount of system memory available to an AGP video card (beyond the card's "local" memory). If your system frequently crashes, set it to 64 MB. If that doesn't help, set it to 256 MB, regardless of the amount of memory in your system.
If you have:
128+ MB ram: Set to 64 MB or 32 MB
96 MB ram: Set to 48 MB or 24 MB
64 MB ram: Set to 32 MB or 16 MB
48 MB ram: Set to 24 MB or 12 MB
32 MB ram: Set to 24 MB or 12 MB
16 MB ram: Set to 24 MB or 12 MB
If you only have 32 MB of memory or less, you really should consider adding more system RAM.
AGP Bus Speed
A commonly encountered problem, especially when overclocking or upgrading to a CPU designed to use a 100MHz bus, is an incorrectly set AGP-to-system bus ratio. For example, someone will overclock his Front Side Bus speed from 66MHz to 100MHz, and if the ratio is not changed from 1/1 to 2/3, the AGP bus will also run at 100MHz. This will in no way benefit your speed, and can even cause problems and/or damage your card. In a nutshell:
Bus Speed AGP Multiplier AGP speed
66 MHz 1/1 66 MHz
75 MHz 1/1* 75 MHz
83 MHz 1/1** (2/3 recommended) 83 MHz (if 2/3, 55 MHz)
100 MHz 2/3 66 MHz
112 MHz 2/3* 75 MHz
124 MHz 2/3** 83 MHz
133 MHz 2/3*** 89 MHz
* This speed is higher than that which the product is designed for. Problems may occur. Try not to use speeds higher than this.
** This speed is much higher than that which the product is designed for. Problems may occur. The lifetime of the card will be significantly lowered. Using a faster bus speed/ratio may "kill" the card.
*** This speed is dangerously higher than that which the product is designed for. Problems may occur. The lifetime of the card will be significantly lowered. This is taking a huge risk and is highly discouraged.
To find your AGP speed, multiply your system bus speed (i.e. - 100MHz) by the AGP/CPU ratio (e.g. - 2/3). For more information, read the AGP and/or CPU configuration section of your motherboard's manual. If you MUST set the AGP bus speed higher than 66 MHz, remember: You have been warned.
For information on these BIOS settings and plenty of others, check out the CPU / Motherboard tweak guide, available in Tweak3D's tweaking section.
Drivers
Generally speaking, the NVIDIA reference drivers work well on any brand of TNT/TNT2-based card. They are also very easy to work with. In some cases however, some additional features (such as TV-out, etc) may either not function properly or stop functioning altogether. Other than that, these drivers usually tend to be the best mix of stability, speed, and functionality.
It's also possible to mix drivers to obtain different features in one set, but I've found that mixing will bring little benefit, and sometimes it can cause conflicts. The end result usually isn't worth the work. It was at one point in time beneficial, when some driver sets supported some features, and others did not. But now, most driver sets have identical speed-related features, and most of their little fringe benefits aren't really worth all the trouble, in my opinion.
In addition, TNT and TNT2 drivers are completely interchangeable. There are currently TNT/TNT2 drivers for BeOS, Linux, and all Windows platforms (even 3.x!).
For the latest NVIDIA reference drivers:
NVIDIA Driver Page
Installing the New Drivers
When installing your drivers, it is best to do a proper install, which involves switching to a standard display type, purging your system of any old drivers, and installing the new drivers. Read and follow the steps carefully.
Step One
Right click your desktop
Choose Properties
Choose Settings
Choose Advanced
Choose Adapter
Click Change
Here you'll be presented with a couple of options. Choose to display a list of drivers. In the left pane, scroll all the way to the top and choose (Standard display types). Then, in the right pane, choose Standard PCI Graphics Adapter (VGA). Follow the prompts, and reboot.
Step Two
The second step before installing the new drivers is making certain that there's no driver "residue" left behind from previous driver installs. If you're upgrading from a previous set of NVIDIA reference drivers, do the following:
Click the Start button and select Find, and then Files and Folders...
Make sure the Find applet is set to search your C:\ drive and do a search for "nv*.*" - without the quotes
Look for any files found in the C:\Windows\System and C:\Windows\Inf and C:\Windows\Help
Select these files and delete them (do NOT empty them from the Recycle Bin until you know your upgrade has been a success)
Exit the Find applet
Click the Start button and select Run
In the Run box, type regedit; this will open the Windows Registry Editor
In the left-hand pane, navigate to the key HKEY_LOCAL_MACHINE\Software\NVIDIA Corporation
Right-click on the NVIDIA Corporation key in the left-pane, select Delete, and click Yes to confirm the deletion
Exit Regedit and hit the F5 key to refresh the registry
If you're upgrading to NVIDIA reference drivers from a manufacturer's proprietary drivers, you have two options. The first option is using an uninstall utility that may or may not have come with your video card. If there is such a utility, you'll find it in the Add/Remove Programs applet in the Control Panel. There may also be such a utility on the drivers CD that came with the card. If you have an uninstall applet, use it. If not, you'll have to take a different approach to "uninstalling" the old drivers. This is where System Info comes in. It's a handy little applet in Windows that displays information about installed components, drivers, resources, etc.. To use it, do the following:
Click the Start button and select Run
In the Run box, type msinfo32
Once System Information opens, click on Components and then Display (in the left-hand pane)
In the right-hand pane, System Info will display a list of information about the display drivers that are CURRENTLY INSTALLED. Each file has a Company Name entry, which you need to pay attention to. If a file's Company Name is either Intel Corporation or Microsoft Corporation, forget that you ever saw it. As for the rest of the files listed, write down the name of each one. Do a Find for these files as outlined in step two (above), deleting each file as you go.
Next, from the System Information utility, select System Configuration Utility from the Tools menu, and select the Startup tab. Look through the list for anything related to your old drivers. For example, when removing Creative Labs' drivers, you may find something that refers to a "Blaster Control," such as bcontrol.exe or blasterc.exe. Uncheck these items, and close the utilities. (If you're prompted to restart, it is recommended that you do so.)
Step Three
Now to install the new drivers.... Make sure you have extracted the .zip containing the driver files to an easy-to-find location. Once you've done so:
(The following pertains only to NVIDIA reference drivers, and may not work properly with non-NVIDIA drivers.)
Right-click the desktop and select Properties
Click the Settings tab, and click the Advanced button
Click the Adapter tab, and click the Change button
Click Next, in the update Device Driver Wizard
Select the radio button for Display a list of all the drivers in a specific location...
Click the Next button and click the Have Disk button
In the Install From Disk box, click the Browse button, and point Windows to where you extracted the new driver files
Click Okay, then Okay again, and in the Select Device window, select either TNT, TNT2, or TNT2 Ultra, depending on which card you own
Click Okay, and then click Next
Let Windows install the new drivers, and click Finish
Click Okay, Apply, and Okay
When prompted to restart your computer, do so. 
