problems with ubuntu 9.04

I've recently installed ubuntu 9.04 (32-bit) on my HP 6715b computer with AMD Turion x64. The first problem are white lines that flash on my screen every time I open a program, move a window along the screen or without any reason at all.

The second problem is that my computer won't start up or shut down without me pressing space or mouse button from time to time.

I tried installing ubuntu 9.04 64x, but it worked even worse.

Please help!

9.10

I know that it might not help you, but is there a reason for you to not install the latest version? 9.10

Other thing you might consider is installing the manufacturers graphics drivers... I don't know what is you graphics card but in general the proprietary drivers for graphics work better that the open source counterparts

Best regards

Duarte

Can you post the output of

Can you post the output of these commands?
lspci
sudo lshw -C video