Uninstall the antivirus software and then reinstall it and make sure you specify the D: drive as the install location.

Better than that, move as many folders of data data files as you can (word processing documents, spreadsheets, digital photographs, etc.) to the D: drive. Then go to the Tools... Preferences menu of each of the programs that save those documents and alter the default location from C: to the folders you have set up on D:, then you should have all the space you need for programs.

while your at it make sure you check in add/remove and see that you have no programs that you are no longer using, if there are remove them and gain space or if there are like 3 copy's of same program such as Quick books, or Adobe .6 and .7 change and get newest delete rest gain space. Do a disc clean and defrag if you can if though it may say not needed(if you are within 10% of space let on hard drive will not defrag) something that will help performance of PC and possible rid you of some problems is do a registry repair program, here is a good FREE on that is also a spyware comb. GLARYULITILIES DOWNLOAD GO TO www.pcworld.com 1. WHEN PAGE OPENS TYPE IN THE SEARCH BOX - REGISTRY REPAIR PROGRAMS - CLICK GO 2. LIST WILL OPEN, SELECT THE SECOND ONE - GLARY REGISTRY REPAIR (ITS FREE) CLICK IT 3. NEXT PAGE, YOU WILL SEE A RED ARROR AND DOWNLOAD NOW IN BLUE WORDS - CLICK 1.30MB 4. NEXT PAGE BLUE BOX DOWNLOAD FREE REGISTRY REPAIR NOW- YOU CAN CLICK HERE BUT REAL SLOW (works on 98, XP, ME, 2000, 2003, Vista) just not 64 bit supported 5. For a faster download click where it says - mirror here 6. NEXT PAGE IF IT DOES NOT START IN 5 SEC LOOK FOR A SECURITY BAR, WHICH IS LIGHT YELLOW AT TOP OF PAGE, CLICK THE OPTION TO ALLOW IF FOR SOME REASON IT STILL DOESN’T USE THIS OPTION: LOOK FOR THE LINE THAT READS CLICK HERE IF IT DOES NOT 7. BOX OPENS SAVE TO DESKTOP OR TO MY DOCUMENTS AND OPEN AND RUN FROM THERE