Cannot Change Graphics on Screen

i managed to get a virus of some sort tonight...i think i removed it from my system, but now i have giant graphics and it will not let me change them in the settings. when i go to display/settings...and try to change the size of the screen, it says i have to restart my computer. then when i do, nothing changes. i had this problem once before, but i do not remember how to fix it. when i go to the control panet/system/device manager tab...it says 3 items are not functioning normallly or need new drivers...when i try to get new drivers, it says i have the newest ones. so it sounds like something is wrong with them...these are the three...

ATITuneP, WDM TVTuner
ATIXBar, ATI WDM Video Audio Crossbar
Bt829Pro, WDM Video Capture for AIW Pro

Please help me with this...i cannot look at these giant icons, and because it is all big, the color is down to 16 bit, so i can barely read any websites. if it is important, i am running on windows 98. thank you.