Hi,
im using windows xp home edition
I have the two default styles Luna and Windows classic but a vista theme i used to use doesnt work it is not in my theme selection but i got the file in my documents when i click on a Windows visual style file it opens the apperence and themes and it just shows windows xp it never did this before i installed windows vista transformation pack 5.5 which i uninstalled
about 1hr ago...so any help?

EDIT:fixed traxor helped me thanks traxor

Perhaps when uninstalling the transformation pack, uxtheme.dll was returned back to its normal state. Try downloading the neowin uxtheme.dll patch from here  and trying it again.