As the subject suggests, I'm having an issue with an out-of-warranty Inspiron 546.

The computer was shut down on Thursday, and when it was powered back up on Monday (today), the fans started spinning, and orange light on the motherboard lit up, and the blue light on the power button started blinking rapidly.

I have:
-tried a new power supply
-unplugged the cd and wireless nic
-installed a known good AGP video card
-unplugged the hdd
-reset cmos
-removed cmos battery, waited 5 minutes, replaced battery

Nothing I've done has had any effect.

I actually left the computer on while I was typing this up.  I looked over a few minutes ago and the power light was solid blue...but no other activity.  Just now I realized that the fans were running at full speed...but sitll no activity.

There was a power outage over the weekend, but the power strip still works fine and the surge indicator is still intact.  I've used a different power cord and plugged into a different wall socket (one in a different building altogether, actually, as I now have the pc in my garage).

So...what do we think the next step should be?

Thanks!