PLEASE HELP ME!!! I tried to upclock my cpu and I had no idea what I was doing. I changed something in the BIOS settings. Something that had options like 1x 1800MHZ, 2x 1800MHZ, 3x and so on. I stupidly picked the highest (9x 1800MHZ) and now my PC won't even start up. The light that signals that it is on still turns on but nothing shows up on the monitor (it's not the moniter as I have tried others). I replaced the cpu and it still does the same thing. PLEASE HELP ME!!!

Try re-setting the BIOS, you do this by either pressing a button or shorting two pins on your motherboard, check your motherboard manual and look for a section on clearing CMOS. Worse case is that you may have fried your cpu, but if you saved your settings in BIOS it can mean that any subsiquent cpu's you fit can also be fried.