Just installed a new cpu fan and have put the system back together but now the monitor is acting like it is not connected. Graphics card is powered with the fan spinning so it is getting power but it somehow is not picking it up.
Also tried an hdmi cable to connect to a television and did not pick it up the signal so I believe the cord is working.
It sounds like you took the system apart when installing the new HSF. It's possible you forgot to plug something back in when putting the system back together. You should go through the READ before posting about boot problems! sticky at the top of the forum. I've been updating it just today, so the suggestions are all relevant and up to date.