No Signal

I just received a modware kit and thought I would try installing it.  I turned off my computer,  unplugged the power cord,  removed the case,  and installed the fan.  I wanted to see if the fan would work,  but didnt want to reattach the case,  so that if it didn't work,  I could remove the fan.  I plugged the cord back in,  and hit the power switch.  The computer started up and everything worked fine.  I then decided to surf the web,  draw on psp,  just mess around for awhile before I reattached the case.  All of the sudden,  my pc shut off.  I tried to turn it on again,  and when I hit the power switch,  the tower started up and the fan came on,  except for that my monitor and keyboard didnt do anything.  When I hit Caps-lock,  the little light in the corner of the keyboard didn't come on.  I tried hitting Num-lock and Scroll-lock,
but that didn't work either.  I then noticed that the little green light on the tower by the power switch wasn't on.  Neither was the red one.  I then tested the monitor.  I pressed the MENU button on the monitor,  and a window came up saying: "NO SIGNAL".  I have tried unplugging the fan and turning on my computer,  but nothing seems to work.  I may have accidentely unplugged a two pin wire labeled "H.D.D. LED",  while installing the fan,  but I'm not sure.  If that wire has any significance,  then please tell me where it is supposed to be plugged.  I really need my computer back,  so if anyone knows about "NO SIGNAL" then please post a message.  I have already tried the simple solutions,  like making sure all of the plugs are securely in their sockets,  and I believe that it may be something to do with the H.D.D LED.  If anyone can help then GREAT!!!!!

thanks,
Walter

You should have a manual that came with your MB that explains where the HDD LED cord connects and in which direction (this is the hard drive light, the red one on your case front). If this is connected across the sleep switch contact or case security switch pins (or other switch pins), it could be shorting the MB. You can also determine by the silkscreening markings on the MB where the HDD LED should connect, but many people have trouble with the tiny size of the print markings.

If your case mod kit included a high-power 120mm fan, that could be taking more power than some stock (200 to 280 watt) power supplies are built to handle.

Or your PSU could be taking a dump. Get a 400W or bigger dual fan one for a replacement.