Lower Your Windows Graphic Settings

Windows XP - Lowering Graphic Settings

Turning off or lowering Windows XP's graphics will noticeably increase the speed of your computer. This is a great tip for older PCs. You can sacrifice some cool animations for performance with this tip. Here is how to do it:

Go to Start -> Control Panel -> Performance and Maintenance -> System.
Go to the Advanced tab then click the settings button under Performance. You will be on the Visual Effects Tab.
Select button that says 'Adjust for best performance' and then hit OK.
That is it. Your computer should run a bit faster and all you lost were some graphics and animations.

Windows Vista - Lowering Graphic Settings

To adjust all visual effects for best performance in Vista:

Go to Start -> Control Panel -> System and Maintenance -> clicking Performance Information and Tools.
Click "Adjust Visual Effects". If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Click the Visual Effects tab, click Adjust for best performance, and then click OK. (As an intermediate stop, select Let Windows choose what’s best for my computer. If this is still too slow then I would select "adjust for best performance")