Windows XP on a Pentium D, sata HD's. Gateway 836GM - Windows XP Media Center Edition. I was on facebook and a couple other sites, browsing, chatting, etc,. Com started running really slow. I rebooted. After POST and before OS can load...black screen with blinking cursor. HD spins and setup still shows it. I do NOT have a windows cd. Even if I did my boot sequence only shows my 2 hard drives and something else that I have no idea what it is (WD-[random letters and numbers]). Can't boot off other hard drive even though it works fine. When I try to load up windows xp from it, it wants validated since I put it in from another computer that went bad. Called Microsoft to get help validating, after 18 calls and 14 hang up's, they will not help me. So, black screen with blinking cursor, no cd, no option to boot from disc. I'm supposing I can put the drive in another com as a slave and replace the system files from the working HD. The problem is, I have no idea which ones to replace. I would just format it and start over but I do not have a disc and therefor no OS to put back on it. It does have a partition on the bad main drive for restoration. However, I have tried everything I can find to make it boot to it so I can do a factory restore but it will not do it. I've hit every F key and every combination of F key's - shift F this and shift F that. Any way Gateway say's to do it, it will not work. Any way people say in forums it will not work. I prayed for answers, had divine inspiration, but it did not work. What to do? Genuine help will be greatly appreciated and you will have my undying devotion.