|Try what Derek recommends in # 7 here:|
I know the symptoms aren't the same with yours but sometimes that fixes oddball problems.
If that doesn't help, sometimes it may just be a loose connection to the screen but since it's a laptop/netbook that's not an easy fix for the user. If it's not a connection issue then it's some other internal hardware problem that may require a shop to fix it.
Is it still under warranty?