I've got just a 1 GHz chip, only 256 in RAM, and I can still play about half a dozen games at full speed. Every other game plays at 65-70%.
1) First I change the resolution on my desktop to the lowest setting possible.
2) I go into the "My Computer" Properties menu and change the 'Performance' settings to best performance.
3) Most important I clock the CPU to 50 on Chankast. The - key on the numpad. For laptops without a numpad, you will have to use the function key to access the -key.
If your operating system hasn't been rebooted in a long time, that could also be slowing you down. After my PC crashed, I had to reload everything from scratch and now everything works faster.