Thanks for quick reply. And what should I notice / care about if I decide to buy online. I heard that I must use same mHz speed for both RAMS. Wouldnt more than 4GB work in 32bit UBUNTU 12.04 ?

It is a problem that affect the whole M17X series. I discovered a lot of forums worldwide with posts like this of people affected by this problem. Even in the dell communities worldwide.

2) I am asking question 1 because this machine had a virus... which upon rebooting to complete removal the machine would show the windows moths flying around and coming together, than a fast flash of a blue screen with white letters, then it would begin to boot again... in an endless loop.