ok.... here's how it should go.
1st off, u need Detonator Destroyer from Guru3d
LINK basically, you launch D.D., then it tells you to go to add/remove in ctrl panel, remove Nvidia drivers, then BACK to D.D. and let it clean out the reamains.
THEN, upon reboot, you NEED to set it up for STANDARD VGA drivers. That most important.
THEN after you reboot again, you are then able to install the new drivers fresh.
I'll be here for a bit, p.m. me, or reply if ya' need more help.
(heck, just click the D.D. link, it basically says what I just posted. shoulda just copy / pasted it durn it...)