Windows Theme screwed :S

Hmm, for some reasons i cant restore my default windows Xp theme back, it went to windows standard, then i changed that to windows classic, and now windows standard has been removed.

I think its all come about since i used some patch that mythos sent me, called "UX Multi Patcher 5.5.exe", which enables you to use other themes of your choice.

Anyway, other day i was in shower and my windows automatic updates were set on automatic, whilst my comp was on and inactive, my computer restarted by its own will for the updates to take place, and since then ive had that windows classic theme, and i cant even choose the default one if i go into properties, sometimes messages pop up as well saying that files in my windows have been replaced by unrecognized versions, i think this is what is stoppin me from changin back my theme, so is their a way i can get these files back or undo the changes that have been made, my desktop looks awful with this theme :(