here is an odd one for ya, i installed mandriva 2006 on my wife's computer. When running KDE everynow and then random lines pop up across screen across anything that is open and stay there. i have found that if i log out and log back in that it corrects but lines come back sooner or later does anybody know what is going on? I checked display properties and everything is set correct. i have also updated the system using mandriva update. i am using a amd 3200 processor, 512 Mb RAm with, 100 gig HDD, display adapter is the sis 256E 128MB intergrated RAM

Does it do the same in text mode? <alt><ctrl><F4> for example and wait
Does the problem is less at lower resolution, lower frequencies?

Is it a dvi or d-sub connection.

I had green lines accross my screen, with dvi only. It is not a display problem.
Not a connection either. It may be the card, or power supply interferences.

Are the cables entangled?

have you got another distro you can install to check it is not a distro thing?

At the end of the day you will have to test the video card on another PC,
once you eliminate everything else

to answer your quetions: 1 no doesn't do that at boot up or in xwm, not used text mode only though
2: no
3: pror to this i had mandrake10.1, suse 10.0, FC4, Slacware10, windowsXP sp2
4: the video card is integrated with the MOBO cables are not an issue.
I am using the native resolution 1280x1024 for my monitor, mandriva detected correct moniotr have to check spec online for freq.

So you confirm it is distro specific.

Then just try the vesa driver (or framebuffer mode even)
backinstore option in xorg.conf may be doing that artefact (??}

Tests other frequencies by editing xorg.conf

I suppose you know <alt><ctrl><backspace>

checked freq spec online and it is correct

Try the vesa driver then.
If it solves the problem then it is a driver issue

check it at 1024x780 and same problem occured, actually i use the menu to log off and then log back in, i'll check drivers then.

i switched the drivers off of the vendor list to the xorg list using the sis driverdo not know if it reseloves problem but wil find out