I've got an HPG5056EA (Which is classified as a HP G5000 by HP). It started playing up a few months ago, and shortly after became unusable.

It seems to suffer from an array of symptoms.
First of all, the laptop would crash but the display on the screen would be a mish mash of colours and such, almost like looking at a view of your desktop through a kaleidoscope.

Then it stopped doing that and simply started freezing, and then it moved onto freezing during boot up.

If I leave the laptop alone for a good few hours, it will start to boot, and I will be able to enter the setup and such. But if I change something and go to save it, then it crashes. Then if I try it again, within a few minutes, the laptop's power button light starts to flash and refuses to do anything. Its connected to the mains and has its battery. I've tried using only the battery (I have 2), and only the mains.. however no success.

I've also tried to replace the HDD, as when I removed it, it seemed to last a little longer before refusing the boot and flashing the power button. This however didn't work. It booted all the way into the Windows XP setup, but said it couldn't see any HDD's. So I restarted to fiddle with BIOS to get it to show, and it started with the flashing lights again.

Also have tried reseating and switching the RAM modules, but it doesn't seem to do any good. Ran the in-bios HDD health test always finishes with a PASS on the Quick and Comprehensive Tests.
I've run out of ideas and hope with this once fun piece of kit. Would love some help if possible and it would be handy for my brother.

Thanks, and if you need any more info just ask.