no signal assistance.

okay, I'm having computer issues.... graphics were freezing on my game type of issues. Area's weren't loading, other npc's and pc's were frozen in place, ect. So took apart the case cleaned shit out as best and as carefully as I could, now there's no signal coming from the tower. I've checked that the video card is in there all the way and rested it a few times. I did a bit or looking around on other sites and tried swapping ram, making sure the processer was aired out and cleaned, and using another monitor. The Vid card is still good due to it working inside my other tower. The motherboard is an Asus M4N68T-M V2, the video cards is a Radeon HD 5450 (Cedar) 512MB 64-bit DDR3 PCI Express. There are no beeps or flashing lights when it's powered up.
(I think I've covered as much details as I can recall and have tried.)
Suggestions?

Care to elaborate on how and what you cleaned your system with? And above the obvious have you checked that your power supply is switched on and everything is plugged in properly cable/outlet wise?

Compressed air mostly, as well as a micro fiber static free rag, the rag was mostly for the inside of the case. Yeah, everything was/is plugged in and connected.

While nagisa could have phrased it better, did you unplug everything before cleaning? Also, how did you clean it? If you used compressed air it's possible that if it was angled badly or shaken just right (or wrong as the case may be) you could have sprayed some liquid which could really mess things up.

Also, where did you use the microfiber rag? I've used some cheap ones that have a bad habit of leaving lint behind. If anything is on the contacts it could cause some problems.

Finally, are you sure that everything is plugged back in, and in the proper spot? On the motherboard it's easy to miss some of the smaller stuff, by either not getting it plugged in all the way or put in the wrong spot.

TLDR; Please describe how you cleaned (where you sprayed, wiped and how; whether or not you unplugged everything) and whether or not everything is plugged back into the proper slot all the way.

ack! totally forgot I posted for help here! heh... >.>;

Anyway I got it all figured out and settled, no it wasn't plugged in or anything that simple... long story short when I was plugging it all back in, I somehow managed to bend a pin in the processer O.o;;

Anyway once my GF somehow magically spotted it and with some more luck, I carefully straightened it out and got it all working again.