Video players crashing or show black window suddenly

[klischee]

Hi

Edit³: No need for read anymore, it's already fixed

I have the problem some players (like ACDSee and XnView) are crashing when they try to play a video or create thumbnails out from it. I don't know why, they played them without problems for months, but since 2 days they crash. I did not installed new codecs or such things, but I changed my graphic card (8600GT to GTX 460) and updated the Geforce drivers to 260.99. Could this have some effect on Codecs or Players?

PotPlayer, MPC-HC, VLC, WMP and others are running and playing videos without any problems.

I tried to render video files with GraphStudio, but it also crashes immediately.

I use Windows 7 x64. Codecs installed: XviD, ffdshow tryouts (x32 & x64), Techsmith, Fraps. I have registered the FLVSplitter from MPC-HC.

Could you help my find out what's going wrong? I don't know what the next step could be...

Edit:
wmv files get played (also in GraphStudio).
Avi (XviD), MPEG2 & MP4/AVC lets crash the tools.
FLV can not be opened by the tools, but no crashes.

Seems only wmv works without problems in GraphEdit and XnView/ACDSee

Edit²:
Hm, semms it has to do with ffdshow. After deinstalling it, everything works fine. That's weird, because the tools which were crashing should not use ffdshow. Let's see what's happening when I reinstall ffdshow.