Jacking your system up to 2.7 from a 1.8 chip is asking for trouble. Your hardware monitor is reporting that your CPU is running at 147o? That's not a good sign. You're burning that processor. Whoever built that computer for you should never have tried to push that kind of speed out of the processor without appropriate cooling. The beeping you are hearing may be some sort of alarm warning you of the high temperature of your CPU. Just as an example, I have an Athlon XP 2000+. At stock speed, the average temperature of my CPU is 102o. Under full load, that temperature rises to about 109.
I suggest bringing everything back to stock. If this is an old hard drive, make a backup of all your important data, format it and reinstall the OS and other needed software. Currently, you've got drivers for an nvidia-based board, yet you are running an ATI board now. Who knows what other garbage is hanging around that is causing you problems.
Your framerate is usually locked to the refresh rate of your monitor. If you're running at 60Hz, you won't be able to exceed 60 fps unless you disable v-sync, or run your monitor at a higher refresh rate.