XnView Software

Has anyone come across this situation?

I set up a Logitech webcam last week, and Skype.
All seemed well until I incidentally went to XnView to look at a short test video, only to find that the display had been darkened to the point of obscurity. I can see the lightest bits of a given video, but have no control over the brightness setting.
I uninstalled Skype & Logitech software but no change.
Have installed VLC media player and it displays the correct brightness for all videos.
No change to XnView player though.
So something's mucked with XnView's player, and I'm wondering how to fix it.

The player uses whatever video codec/driver which you have installed on your computer (not providing its own). Some of these have controls to adjust brightness. I haven't looked at it, but there is a program mentioned in "misc" section which might help identify what components are being used:
•Gspot video codec identification utility

Very nice tool!
Looks like I'll have to do some digging around for the default codec, probably just reinstall my video drivers.

** update: have just reinstalled graphics card driver - fixed the problem.
No thanks to Logitech, then, for overwriting it.

despite that, I find the player works half the time anyway, and refuses to play the other half.
No change in codecs!