My computer was working fine (I have a dell XPS t500) with the exception that I only had 128mb of ram. So i decided to up grade my memory and add a stick of 256mb . Fine, I did that then the unexpected happen it gives me a black screen saying "No Operating System Found" . My problem is this computer was a hand me down and i don't have any restore disk. Any inexpensive ideas on how to solve my problem?