Any idea??

[JD]

I have a laptop with a Turion 64 x2 (1.6 Ghz) processor, 512 Mb of ram, 
an ATI X1100 video card, 100 Gb of hard disk and i'm using ubuntu hardy.
A lot of times my pc get stuck and when the desktop effects are enabled, 
a lot of little lines white and black appear and also it gets slow. I 
used ubunu gutsy and i had to do a lot of things including to reinstall 
the kernel following some instructions that i found on ubuntuforums to 
get the effects and to improve my pc ... But now i can't find my problem 
solution over the internet... so... does anybody has an idea??