It's a mystery! So, a few weeks ago, I started noticing the smell of burning plastic in the room that my desktop PC is in. It was sitting on the carpet, so, I snagged two extra travertine tiles left over from my "kitchen project" and placed them underneath... thinking that maybe it was getting too hot from sitting on the carpet. A few days later, it shut itself off while I was in the middle of writing an email. It did seem like the power supply was overly hot at the time off shut-off. As a few days passed, I focused a large fan on the tower, it kept happening. Shut- off, every time I went to use it. So, finally, I opened it up (I'm no "expert," but I can certainly find my way around the innards of a computer!), it was dusty, dusty, dusty! I removed the power supply, opened it up, and removed the sheet of dust, and hair from inside of it. I figured that it might be that dust and hair that I had smelled burning. Nothing else from inside the tower looked melted, or damaged at all. So, I cleaned it out, and put it all back together. Turned it on, and the black screen appeared, and in white, it said, "Restart and select bootable device." What did I do? Now, it won't boot at all, just goes to that black screen everytime. I'm positive that I put everything back together exactly as it was.... If it was a power supply issue, it wouldn't ask for a "bootable device," would it? My guess is that maybe it's the hard drive? Like I said, none of the boards looked damaged, all wires were in good shape, etc. Did I fry the HD? Please help!!