Kubuntu locking up

[MrMaN383]

I'm using kubuntu 7.04, tried same version of ubuntu and i experience the same problem. the screen either goes completely white or has stripes or streaks the same colors as were just showing before the crash. i have to hard reboot and occasionally my cursor will then show as a blurred block at the log in screen. if i hit control + sys + backspace and then reboot it goes away. this crash occurs regularly, sometimes within a few minutes, most times several hours and occasionally a few days. it never happens when im away from the computer and almost always occurs when im using firefox although sometimes it will do it when another program is being used. it seems to me like my integrated video card(VIA K8M890 chipset) might be the problem, locking up if it cant handle frequent changes on the screen. however videos work just fine at full screen, can run for hours and wont lock up or hesitate.

it even did it when i was just running off of the live cd. the memory test from the grub menu said i passed with zero errors. its happened when using the konqueror browser as well as other programs (ktorrent, adobe pdf files, maximized pidgin chat windows) . it just happens most frequently when using firefox. i believe this is because A) its the program i use most frequently at full screen and B) it seems to happen when going between tabs quickly, scrolling a page too fast or a new page quickly rendering. if i make a habit out of scrolling slowly and in increments and quickly minimize the browser after clicking a link (before the new page can render) it seems to avoid crashing as frequently. nothing shows up in the system logs when the crashes happen. anyone have an idea where to start??

[Gorganzola]

Definitely sounds like an issue when a specific library that is common to the apps you listed is called. The problem is determining which one. Perchance there is an update for the drivers for the VIA chipset.

You may want to see what there is available here as well:

http://ubuntuforums.org/