I have strange problems with graphical interface - programs are randomly having problems, sometimes X restarting. For example, I tried to watch movie in vlc

:~> vlc
VLC media player 1.0.3 Goldeneye
[0x804f3a8] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
...........................................................
header damaged
header damaged
header damaged
.......................
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::setClipRegion: Painter not active
QPainter::setClipping: Painter not active, state will be reset by begin
QPainter::begin: Paint device returned engine == 0, type: 1
[????????] x11 video output error: X11 request 42.0 failed with error code 8:
BadMatch (invalid parameter attributes)
[????????] x11 video output error: X11 request 132.19 failed with error code 11:
BadAlloc (insufficient resources for operation)
X Error of failed request: BadAlloc (insufficient resources for operation)
Major opcode of failed request: 132 (XVideo)
Minor opcode of failed request: 19 ()
Serial number of failed request: 706
Current serial number in output stream: 707

Blender not always correctly opening file, sometimes colorful squares or lines are visible through all screen, either first or second blender screen. X randomly crashes some times in a day, redirecting to login screen, also I couldn't start all games (not with wine, linux games). In short - strange problems, and I'm not sure about their origin I just guessing, that this is because of nvidia 190.14 driver installed (at least nvidia-config showing that), but just guesssing. Video card is GF 6200, if this matter. DE is KDE4. If you need any more info I'll provide you, just ask.