About a week ago i took the cover off my computer to dust it out. i pluged the moniter and all my hardware back up, but for some reason i cant get any picture on my moniter. im pretty sure its not the screen b/c i hooked up an old CRT to my com and got the same thing. the computer comes on when i boot it up but i just get a `no signal` on the screen. if you have any insight or knowledge of this i could use it!