If yes, is caching enabled? I'm wondering if the Jar is in cache of java and can be deleted there by dumping cache ? Conversely you could install CCleaner which will empty BOTH Sun Java Caches, temp files, history dat., etc. when run. Links Here:
http://reviews.cnet.com/5208-7813-0.html?forumID=32&threadID=105074&messageID=1263885
Don't know about the Class file. Would date(last January) indicate it's been there til now or just where it landed? If latter, I suspect you could delete as if its Documents & Settings, wouldn't there be clean copies of that file in back sys restore files? ( or is .jar another name for sys restore files(along w/system volume, backup files & 1/2 dozen others (LOL!)in which case easiest would be to disable/re-enable (dump files) system restore.
Did AVG not offer you the choice of heal or delete or quarantine? Not Expert at this stuff. At least you won't feel ignored 'til one comes along (LOL) and sometimes I get lucky !! Patience= virtue! 
I scanned with avg and it first said I had two infected files but then it said I had one. - one was Beyond.class and the other archive.jar (with numbers and letters following.) Right now I'm concentrating on Beyond because I found the file. It's type: Classfile, date 1/26/05, location Archive Root Directory. Size 3kb. I use windows xp, have zone alarm, and avg is updated automatically daily. Can I just delete the file from C\documents?? Thanks.
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