Linux.com

Hello all, I have a semi-old dell desk top that is eaten up with viruses and it is running on windows xp...which I have conveniently lost the installation disk for! I have a laptop with which I still run xp... I was wondering if anyone knew how to upload xp from my laptop to my desk top and if not if anyone knew how I would go about loading linux onto my desk top after I reformat it??.... using a usb flash drive... I would also like to know if my son will be able to play games on the linux os just as he did on xp.... games such as sponge bob, the sims, star wars... all ea games.... too much money down the drain otherwise ... not very computer savvy here, so any help would be greatly appreciated.