your computer like which Windows you have, How much memory you have, type and size in MB of Graphics card, possible Make/model of your pc if branded name like Dell, Tiny etc.
What you use the computer for also would help us tech guys to give you the help you need.
Good File management and system configuration is a must and first to check. Try and remove software that you know you do not need like old games etc but make sure they are not deleated taking system files.
AOL ISP software can if you use them hog up your system resources for example. If you have Win 98/98Se ME or XP use the Disk clean up and clean away the junk files, custom screen savers from 3rd party softwares can slow things down and heavey picture 3rd party graphics but mostly on the older computers.
Many things to check and do, maybe you just need a memory upgrade, or a new graphics card but we reading here are unable to gove a more direct reply with not knowing what you have in your system.
Please post back with more details and Happy New Year.
More ram. What sort of CPU is it ? Is it a celeron or duron ? Get the latest graphics drivers. 42.01 for XP or 2k these are betas though, But probably the best to date. Your graphics card is good. Your CPU could be letting the side down a bit though. What games are you wanting to play ? Also try disabling Vsync and antialiasing. These will drag any system to its knees unless you have a 3Ghz P4 and and a Radeon 9700 pro