Last two months or so, my CPU stopped working. The computer stopped recognizing the HDD, so it was rendered useless for that duration of time. Now, we bought a new Hard Disk Drive (upgrading it in the process)so it can finally work again. So yeah, since it was new, I had a new OS ready for installation so I went to Setup Utility (Clicking delete while it is in the POST) and made the priority drive the CD-ROM and the like. Before I was able to save it though, it suddenly hung. After clicking the reset button, the LCD's green light did not appear again. I opened the CPU to do the routine stuff (making sure that the cables are correctly connected and the like) and tried it again to no avail. I removed the memory module from it's slot so I would hear the regular beep, but I didn't hear a thing. The onboard LED is still lighting and the fans are working as well.
What could be the problem? Should I buy a new motherboard already or just change something for the better?