I've had this computer for about a year; my first homebuilt PC. Everything as been working fine, but today it wouldn't boot up. I took the system and reseated everything. Worked like a charm. Went to restart it later today and it didn't boot back up. Opened up the case yet again and this time found the 2x2 power cord had somehow come undone. plugged it back in and now my ccomp won't boot. It seems to boot up w/o the 2x2 plugged in but nothing shows up on ym monitor.
What the link does, if you read it, is suggest that you be specific with your problem...I.E. give more details about your system, mobo, CPU, PSU, GPU, amount of RAM, number and types of drives, etc. With more details provided, someone may be able to help you quicker...
Just an observation... The 2x2 power plug, when inserted properly, locks in and it is VERY unlikely to just come unplugged. So either you didn't put it in properly, or someone is messing with you.. Also the 2x2 plug is required for your CPU to be able to boot.
+1 to listing your complete computer specs if you expect to get any meaningful help.
Yea, the 2x2 power connector supplies power to the CPU. You have no chance of the computer working without that plugged in. I would go through the checklist in the "READ before posting about boot problems!" sticky at the top of the forum. I would pay special attention to the section about RAM. A good majority of no-boot problems that I've seen were caused by faulty RAM.