My computer has stopped starting from this week.
I have made no changes to it at all.
I have opened it up and cleaned out the dust since it was overheating.
There have not been any symptoms until this week.

My computer doesn't have a POST beep anymore.
I replugged the RAM yesterday (Same Ram, switched slots), and it worked!
But the computer would still freeze, except on Safe Mode (With Networking).
I reformatted the C: drive, and when it finished, I put in some saved songs, and Mozilla Firefox (With my bookmarks history etc) from a CD. When I opened Firefox, it asked if I wanted to import any files from IE, I clicked no, and then it froze again.
It might have been a virus from some temporary files or something from Firefox but it is too late to check.

I had to do a forced shutdown by holding down the power button.
I removed the RAM, and it made a long beep when I turned it on, so, like 'yesterday', I replugged the RAM in.
No POST beep this time. I removed the RAM again and tried to turn on the computer.
No long beep at all now.

The fans run, the LED's are on. I unscrewed the back fan but it seemed like it was on pretty tight anyway.
The thing is, when I open my computer, if I lift a bunch of red black and yellow cables connected from the CD Drive, Motherboard, back fan, and this "Maxton QuickView" thing under where my floppy disk drive should be, it makes a stronger fan/engine sound which I usually hear when I start up my computer, which used to lead up to a POST beep.

I even tried reinserting the circular battery in the motherboard to no avail.

Thank you for reading my long post. And thanks in advance to any helpers!

I have near pinpointed the cause. Lifting up those cables as I start the computer seems to make the POST go through. The moment I let go, the computer froze. What can I do about this? The cables are connected to CD Drive, Motherboard, back fan, and this "Maxton QuickView" thing. The majority of the cables seems to be from the fan.

Thanks in advance.

You may have a loose connector somewhere. How did you clean the dust out? I trust by blowing it, and not vacuuming it. Either way, you *might've* loosened a connector.

First standard answer: disconnect A/C power, ground yourself to discharge all static you may have built up, then unplug and re-connect pert near every connector and device in the computer. While you are doing so, feel the wires for anamolies like too hot or broken wires or most anything that doesn't quite feel right.

Be gentle, careful and firm. And be patient and pay attention to what you are doing. Computer disassembly and assembly are not for those with severe ADD.

Mainboard power connectors can be difficult and may require squeezing a release tab to allow the connector to be removed.

Memory sticks generally have push levers at either end that lift the memory out; installation often requires significant pressure.

Be sure you check all floppy, optical and hard drive connectors, power and data. You might be able to skip fan connectors if they seem to be running OK.

If you can't unplug a device or connector, at least loosen it and solidly re-seat it.

See if that helps.

BTW, that one device seems to be a "Maxtor QuickView":