Well I agree with point made above, such as Bios, Bad Processor, Bad Memory etc.

It could also link with bad power supply, but then that means the problem would still continue.

Are you using a seperate graphics card now?

I am asking this because, onboard graphics uses some of the Ram to run it. So after adding in a seperate graphics card, there will be more Ram left. But this shouldn't be a problem to be honest.

Do you have some kind of 'Gateway update' software? My Asus netbook has a program 'Asus Live Update' which updates my netbook now and then. I also have something similar on my Asrock mobo...

Either, why worry about the problem? Your computer works fine now