I know there have been many similar threads, but I could not find an answer for my specific problem.
My PC locked up during a resource-heavy game, I had to do a hard reset. Then WIN7 couldnt boot up, it just showed a blinking underscore instead of the Windows splash screen. In the BIOS everything seemed fine. I did system repair with the WIN7 boot cd, it said the HDD was faulty. Tried a different HDD, this time an old, but reliable PATA with a different cable instead of the previous SATA. Installed Linux Mint on it. When I try to boot up from this HDD, the result is the same -- blinking underscore in the top left corner on a black screen. No beeping sound though. In the bios the hard drive is visible. I know the PC is not completely ruined, because I am actually writing this, using the linuxmint boot disk. I can see the hdd, I can browse the files.
I tried a few tricks, switching memory slots, clearing CMOS, nothing seems to work. Is it the motherboard?
OK, so the first HDD was faulty, the replacement works though. It booted up in the end after I pulled out the UTP cable, now it works fine. (weird... I disconnected every cable when I cleared the CMOS, and it didn't do the trick. I had to boot up with only the keyboard and the monitor plugged in.)