how serious are multiple filesize/filehash errors?

as a minor gripe the default ‘lasts forever’ cookie is blocked by one of my security products with no alerts so i spent 15 minutes trying to figure out why i couldnt log in… until i clicked 1 month instead of forever, and viola it logged me in… now for the basics…

I am running windows xp home, sp2+ automatic updates.
av software: mcaffee 10, comodo av, comodo boclean.
firewalls: 1 hardware router, 1 satelite internet router, comodo, prior to comodo ran mcaffe, on prior installs ran zone alarm.
mcaffee has detected and cleaned numerous Potentailly unwanted programs, including several dlls, and some system restore volume items. comodo av is still profiling (5 hours later) but it has found that many many files have a filesize or filehash mismatch of the 10% or so of files that it recognizes. for example there were over 1200 file size mismatches in the first 5 hours and over 900 filehash mismatches. although as a cavet this system WAS reinstalled several times without formatting, (and thus the massive glut of files) and most of the mismatches are older files, or backup files, some from another pc, but the fact that both comodo boclean and comodo vengine were filesize mismatches (and i’d just downloaded them today) was strange, perhaps the av has old filesizes for versions released before today?

It also found file size mismatches for a video game i play online, frequently on this computer… and there havent been any updates to that game in a fair while. (more than a month, possibly more than 2 months) a popular game by blizzard… there are so many files it detects that are obsolete files that should be deleted anyways that i’m not in total shock and horror at the count size (since i converted it into a table in ms word)… it’s now 6 hours into profiling with about another 15,000 files to go… it just cleared 20k recognized files and now that I’ve edited it’s 6.5 hours into the profiling…

I thought I was closer to this thing finishing than this, hopefully if there is an infection comodo av will find it, I was also suspicious because of a recurring error with windows chkdsk, but thoguht that the error was due to my backup files some of which were on a bad HD i recently sent in on an RMA, a HD that got so messed up i had to run chkdisk to restore the files to several directories… afterall, that was basically the microsoft line that the recurrent nature was due to a limitation (bug) in windows chkdisk that didn’t allow it to fix a certain kind of filesystem error… and that if your dirty bit came back clean it wasn’t a serious issue… oh well, i just realized it has a another 20,000 files (on d:) to go, i’m gonna have to wait til morning… i’ll post again when i can see the results…

well, the only thing comodo found was an old zipfile with some remote administration tools i used to use… i’m going to assume the filesisze/hash errors are because those files aren’t actually being updated, and the few that weren’t in that category were because of the av list itself being behind the latest versions… at least that’s my best guess… the av scan of the system took 8 hours though… after 7 hours of profiling… i guess there will only be scheduled night time scans with comodo if it takes that long…