Did you use any type of grounding strap attached to your wrist and attached to something metal on your Mac?
You used a towel too get the dust out!
The towel might have caused a static discharge and damaged some components?
Should have been using cans of compressed air to clean out the dust.
Last thing you should've used is a towel inside the Mac.
There is a half-height AA battery called a PRAM battery.
If your Mac has been off mains power for any appreciable length of time this battery may have died.
Replacements batteries can be found at Radio Shack stores or cheaper to purchase here.
Yes, used a paper towel to clean the metal potions of the chassis (exterior, not near MoBo) and used air to blow out dust from MoBo area PCI area and power supply.
Replaced the PRAM battery with a known good one (i have several for various Macs), with same result. Checked voltage on 'old' one, it was at 3.6V, so put it back in.
I suppose it could be a static discharge, but I was careful not to get near anything that I thought might cause a that situation.
The personality card may have shifted just enough so that it is no longer fully seated in the slot. Take it out and push it back in fully, then do the CUDA reset button again. The personality card is the one next to the PCI slots that has the audio ports (and optionally some video ports in some versions) also known as the WINGS or AV card. I think you have to remove this to get to the battery.