Display driver problem

Hello

I'm using Asus laptop and one day it started freezing a lot. (complete freeze where alt+ctrl+del doesn't work)

So when I tried using recovery disk, the laptop completely stopped working after it tried to configure windows for the first time. I tried booting it using usb linux (damn small linux) and found out that i couldn't access any of the hard drive.

So i ran to the store and bought brand new internal hard-driver, same SATA model with slightly higher capacity. (I also added 2G RAM. I checked the compatibility so i doubt this was the problem.) Now I can run vista but the screen is all messed up. (it has purple virtical bars everywhere!)

I tried to install Windows XP instead after this half-successful recovery, it again gave me a "cannot find hard disk" error.

One after another, it failed to detect video card after the reboot.

It doesn't seem like a hard disk failure(since it's brand new) nor the graphic card problem to me. is there anything more I can try?