Game was going fine. Had removed my Downloads folder and was adding it back gradually. Only had 6 folders left and after adding them I now get a white rectangle with The Sims 2 at the top, a Red X in the middle and a place to click OK. Cant do anything, wont load the game at all. Have all expansion packs except Pets thru Mansions and Gardens Stuff. Looked at Folders and files that caused the problem and don't see anything unusual but there are a lot of files involved. Removed all of these but didnt help. Any suggestions.

Have you tried the obvious, like deleting cache files (that's one of the most common problems with this particular bug, especially after moving around downloads)?

You are right, yes I did delete the cache and all is well again, Problem solved, sorry for taking up your time.

It's easy to forget, and those error boxes can be a bit panic-inducing.