Hi Jacobo, like Steve mentions it is likely to be a problem with the graphics drivers.

Probably something to do with the graphics driver not cleaning up the allocation of video memory when programs are exiting. If all the card's video memory is used up then a new program that asks for video card resources could fail due to lack of available memory.

That's my best guess from your description.

I would definitely recommend updating to the newest version of your video card driver to see if it improves the situation.

Otherwise, rebooting the machine will force the video card to start in a fresh state.

This shouldn't normally be necessary, but if your video card driver has a bug in it and is not behaving properly all kinds of strange things can happen. Video card drivers are very complex so unfortunately bugs in them are not unusual.

- Michael