It seems to happen every time I do a cabinet cleaning. I turn it off, detach my video card, dust off all my fans, reattach the video card, turns it on and blam, nothing works. This time it's the monitor that's not displaying despite being connected. Its ON button is blinking so there's power to it and it's connected properly to the video card, as I get the "cable not connected" message if I detach it. I've tried attaching my video card multiple times, but seeing how it fits the lock and slot every time, there's not a grand error margin there I reckon. I've got this "cluster" of wires inside the chassis, which, if pushed or pulled in the right direction, can supply power to my motherboard or "connect" a cable that wasn't recognised as connected before. Is there an internal cable that's vital to the communication between monitor and chassis? Also, if it's any help, the characteristic "beep" at startup is also missing. Perhaps it could narrow down the problem area?

Hopefully you didn't use a vacuum...that's one of the worst things you can do due to the static charge that builds up in the hose. It could be that your video card isn't fully seated in it's slot, but if that's the case, you *should* be getting a beep code error. The fact that you're not getting the single POST beep isn't a good sign. I don't know what cluster of wires you're referring to...the case wiring? That shouldn't have anything to do with it. Other than the power button & reset button, those wires are usually just for LEDs, unless your case speaker became unplugged & that's why you're not getting any beep(s)? Make sure the main 20/24-pin ATX plug is securely connected to the board along with the 4-pin ATX12v plug. And if your video card requires an AUX plug-in, make sure it's connected.

"Also, if it's any help, the characteristic "beep" at startup is also missing." That means your motherboard is not working. Try reseating the motherboard power connector(s).

Try reseating the RAM as well. crappy OEM comptuers...

Most likely the dust gets into the sockets. Pulling them in and out will probably clear the connection. Best in future to leave the connectors in place when you do your cleaning. some other bloke...

Thank you all. jam - I used a brush for the fans, though I did use a vacuum (lowest power) to suck up the small gathering dust piles (mainly in the case and a few spots on the motherboard). The "cluster" is indeed the internal cables from the power supply in the case, that's clustered together in front of my RAM/ATX. Usually, when I've been "inside" the case and it won't boot, pushing that cluster around a bit helps (like when the mobo light bulb is faint). Despite the above, all cables seem to be tightly secured in their slot (as they should be, seeing how I only removed one before this entire incident - the cable from video card to monitor). I tried reseating the RAM as spoonman184 suggested, but I still don't get the beep on boot. Also, as Derek suggested, I tried reattaching the video card to see if dust could be the problem, but I may not have done it thoroughly enough.