Computer 'forgetting' certain file types and dwwin.exe DLL initialization failed
The last couple of days, something strange has started happening with Windows. When I first start up the computer, everything is fine but after a while it is almost as if Windows 'forgets' certain file types. Any picture format will not load in the Windows Picture & Fax Viewer (it either says 'Drawing Failed' or just doesn't work at all) and all files used by Windows Media Player revert back to what I guess you would call the generic icon, although they still seem to work okay. Also, when viewing a folder with pictures using Filmstrip or Thumbnails there are no previews. I thought that the fact it only happens after Windows has been running for a while might indicate a virus, but I have an up-to-date virus scanner and it says the computer is clean.
Not only that, but every time I shut Windows down since two days ago, no matter how long the computer has been on, a box pops up saying;
'dwwin.exe DLL initialization failed'
'The application failed to initialize because the windows station shut down'
I tried doing a system restore from five days ago, but the problem is still there and I also tried the 'disable error reporting' method, which got rid of the error but not the problem with the files.
Could anyone give me some advice? Thanks!