My dad has a computer that became inoperable last week. Although I'm firmly on the fence he has a feeling that its due to my Auntie when she was going through her emails when she was a staying for a week, and may have opened up an attachment that she shouldn't of. Now whenever you boot up windows it goes through the boot up screens and then goes to the Windows 7 loading screen, 1-2 seconds later the computer reboots itself so you have a infinate loop of rebooting with the same process. The following is a process of what I have done: -Advanced boot up mode; gone through Safe Mode, Last Known Good Configuration and Enable Low-Resolution video (640x480) -Repair Windows Installation; Attempted both from the official Windows 7 (x64) Disc, and a System Repair Disc I created from my own computer and tried it on his. The Repair process does not detect any problems with the Windows Installation, so does not conintue the process, but the computer continues to loop. -Perform a system restore; the same problem occurs -Gone through a memory diagnosis; detects a problem with memory, although it never mentions where the problem occurs. -Swapped around memory, changed out sticks; Initially my dad had two sticks of DDR3-1333 2GB, which I then proceeded to take one out and tested one in all slots, then I did the same thing with the other. After that failed I went to use my own Corsair DDR3-1333 4GB and the same thing happens, and my Ram worked too when I put it back in my Rig, so I will not put this problem down to corrupt Ram, albeit it may be a problem with the mainboard. I'm currently in the process of doing two other things that may solve the problem, but I'm not sure. -Delete video drivers; The problem thats occuring at the moment seems to emulate a problem that I have had on three seperate occasions, twice with Vista and once before with Win7, whereby when I'm installing the latest graphics drivers, either through an interuption during the process or a corrupt download would cause the installation to be corrupt, and I had the same problem as my dad is having now. When my 9800GTX became unusable I upgraded to a GTX470, but because I had the wrong drivers installed for that particular card, the problem again occured. So I'm wondering if deleting the video drivers will prompt the graphics card to work from its default setting. Then its just a case of downloading the latest signed drivers. Just to note I have never done a memery diagnosis when I had graphical issues, I have just reformatted the computer. -Restore factory settings; failing the above I am already backing up my Dads HDD to a portable 750GB HDD before I attempt to reinsert the Drive to my Dads computer. If the above doesn't prompt the device to work I'm going to restore the computer to factory settings and hoping for the best. Unless anyone else has a better idea, I'll continue to do this.