problem still persisting

I recently started getting the blue screen with an error message, in several languages, The top one in English reads:

"You need to restart your computer. Hold down the Power button for several seconds or press the Restart button."

So I decided to replace the internal hard drive with the help of this forum (thanks to those who gave input)

The old one was a Fujitsu 60 GB and the new one is a Fujitsu MHV2120AH-R 2.5" 120GB PATA 5400 RPM.

The computer worked fine for about a week but I noticed that it does not "sleep" properly and now I am getting the error message again.

Is anyone familiar with this screen?

I don't know what the others suggested previously.

Have you tried the hardware test DVD?

I've had that screen before, it was a bad memory module. Confirmed by the hardware test.

That's a kernel panic. It can be caused by RAM issues, among others. Have you done the PRAM resets, etc?