Skinning Programs/Utilities

So I've got a bit of an issue, I'm seeking advice but also wondering what you guys think of desktop skinners, those programs and utilities that let you change the way your GUI looks. Up to now I'd thought they were too much trouble (instabilities, drain of system resources) for something that only vaguely bothered me, but I recently figured I'd give them another shot.

On a fresh installation of WinXP Service Pack 2, I installed a UxTheme patcher. It's a little different from other "devices" of its ilk because instead of running a program on startup, it directly modifies the system, such that Windows itself can select new themes from the "Display Properties" menu. It worked fine for a week or two before the following happened:

-I was fooling around with the different variations of a skin I'd downloaded (I had 3 or so oddly-named versions of the same skin, I was trying to figure out the differences between them), and while doing this my system started reverting to a hodgepodge of the default Windows style and the one I'd downloaded. I did a reboot, which seemed to solve things...
-Now I can't remember if this next part happened before or after this episode of -fiddling, but an issue happened where, after 4, maybe as many as 6 hours of computer use (listening to music, running µTorrent, browsing Mozilla Firefox for most of that time period), all text on screen would go blank (in windows, the borders at top, text in the taskbar) while most everything else remained. After about a minute or two of this, the computer would lock up and have to be reset.
-It's been like that ever since, even after I "removed" the utility and restored the original file. I currently have Microsoft's Zune theme, it's the only alternate theme XP will allow without any third party stuff. The lockup still happens, a couple times it hasn't gone blank, I've just gotten a BSOD and the computer has immediately restarted.
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What went wrong here,
was it the patcher? I may have used an outdated version, it's currently circulated as UxStyle. Is it just a bad idea altogether to try and skin WinXP?
was it the theme I used? This is it right here, maybe the guy didn't debug it well enough?
was it a completely unrelated case of malware? I may have caught a wrm from a computer on my home network. I have avast antivirus and it doesn't turn up anything, but with my luck I always get malware that slips by my security programs.

Should I reinstall windows over this? I can live with the problem as it is, but it's disconcerting nonetheless.
My major reason for not wanting to reinstall windows is that it'd be a pain to back up everything and retrieve all the miscellaneous drivers and programs I had to track down the last time I installed windows, but if it sounds like this could only get worse, I'll do it.

Personally I wouldn't have used a third party software in order to modify a critical element of the system.

I myself have patched my themes file through manual means of using a file-replacement utility. Who knows what that Ux theme patcher could have done or what could have gone wrong.

Anyways, if you can find a backup (if you were smart, you would have made a backup like I did) to that uxtheme.dll or whatever it is, replace it back to default with a special system file replacer program. It's been so long since I have done it, I don't remember the program that I did it with myself.

If you're a person who does system restores (I'm not), that might fix the problem too.

However, you should also look into the possibility that this patcher program might have affected other parts of the system as well, after all, it's altering system files. Explore any other things that the patcher might have done that may have compromised system stability, if patching uxtheme.dll doesn't fix anything.

If all else fails, I clean install of XP should never fail, but I would plan on upgrading to 7, after all there's a vulnerability in XP that remains unfixed.

First thing's first, get uxtheme.dll fixed.

Also if everything is working alright, I use a window decorating program called BB4Win which overhauls the entire desktop to a more minimalistic setting.
BBClean mod is my favorite:
http://www.bb4win.org/comment.php?comment.news.41

Hey now, no need to take up that sort of tone. Supposedly my patcher created a backup which would be restored if I ran it again, and I tried that, but the problems persisted.
Just to be safe, I've just downloaded UxTheme from one of those websites that archive various dll's, and replaced the one I had, but the files were roughly the same size and "file modified on" dates, I'm pretty sure I had the right one and the problem was still happening.
Still, I'll check to see if this fixes the problem and report back.

I'll also give this a try, but not before I try to settle the crashing issue. Thanks very much for the reply.