Dell Dimension E521 powers on, fan runs, no video

I posted this as a reply to another post, but wanted to post this so that it will hopefully help others that encounter this same issue. The problem is that the PC was working one day. The next time it was powered up, all I got was the fan running at full speed and no Dell splash screen, POST or anything. So the following is how I fixed my problem.

I just went through this same problem with  a Dell Dimension E521. The PC was working one day then all of a sudden you could power on the PC and the fan would run at full speed and nothing. I searched all over looking for solutions to this problem and I found lots of "try this and try that", but never actually found a post where someone actually fixed this problem.

So, I bought a new motherboard and installed this and this did not fix the problem. This was based upon other posts. I then replaced the power supply because of other posts, but still had the problem. However I now noticed that the lights on the front of the machine indicated a hard drive problem. So I pulled the hard drive and tested it in another machine. All I did was just add it as a secondary drive to be sure that I could read the drive. And since I was at it, ran some anti-virus software on it to clean up anything that may be found. So the drive was good although the idiot lights indicated it wasn't.

At this point I was at a standstill, but then began to think about the symptoms. Fan runs and no startup messages or Dell splash screen. So I purchased a new cpu. The PC originally had the AMD 64 X2 3400 cpu, but I couldn't find a new one of these so I bought an AMD 64 X2 5600. I received it today, installed it and voila....the PC works again!

I know that this was kind of a long post, but I wanted you to know what I went through to get this working again.