XP Style "Luna" Broken

If I change my Theme to "Windows XP" in the Display Settings dialog on my XP Pro SP1 PC, the screen goes completely black apart from the icons (and what fun it is restoring sanity ). If I avoid committing the change, but switch instead to the Appearance tab, everything in the preview is black and the Windows and buttons drop-list box is empty. I know from another XP machine this drop-list is supposed to include an XP style, but mine doesn't. This problem affects all users. I've tried replacing all the Luna files and directories, but with no benefit.

I do know someone else with the same problem on his XP PC.

Anyone know what the solution is, please?

 

Sorry - I forgot to mention I had been down the route of checking the Themes service is running, and it's running OK. I just ran sfc as you suggested, thank you, but it neither revealed anything nor fixed the problem.

 

OK, thanks. I did try installing SP2 but it made an appalling mess of my PC which took months to sort out (see one of my previous threads). Apparently I wasn't the only one.

Regarding this particular problem, I've seen others on the net complaining of the same, and I personally know one other person who is stuck with it (in fact he's had two PCs do the same thing), so it appears to be a bug in XP. What I haven't managed to find is the solution.