Should I be worried?

I'm using bios F5e and sometimes when I reboot the screen goes black just before post. "Odd..." Sometimes it also doesn't recognize my HD. I have my system overclocked to 450FSB but temps are as stable as wolfman jack. I've run F.E.A.R., Warcraft III, Aquamark... Everything seems cool. Can't quite figure it out.

I have the PCI-E manually set to 100 so it shouldn't be overclocking the video card. I guess it could be a RAM issue... but I've touched the ram and it seems fine... Any ideas?