Bit of a problem...

Right, I bought an Asus G1sn a few months ago and it ran smoothly at first. Then it started to hit some issues. The Idle CPU usage skyrocketed and eventually it became incapable of even playing yonks old software at a decent framerate. So I called Asus and told them about the problem but they directed me to an online form or something. I was told I needed to do a system restore before they'd look at it so I did both the system restore thingy that's in vista then using the discs that came with the laptop after that didn't fix anything. But it didn't work either. Part way through the reset it just powered down and wouldn't come back on again (I'm guessing there pretty much was no OS on it.) and they took it in for repairs. I thought; "Great - they'll finally fix the isues I've been having now." Because I'd written how it had gotten ridiculously slow and that restoring it didn't solve the issue. They sent it back only having done yet another restore, as evidenced by the letter than came back with it. So I filled in another form saying that the problem was still there. They made me restore it yet again and they did exactly the same thing when I sent it back. Three times it's now been back to Asus and they don't seem to even seem to be listening to me.

What the hell do I do? :S Any help is much appreciated.