You sound savvy enough to have treid the msconfig route, but if not try it and comb out as much unneeded stuff as possible. I'd also try a bios update. It really isnt that hard. If your lucky you can do it using a usb stick, or if not go and find yourself a fresh unused floppy, as an old dusty one from the bottom of the cupboard is a bit risky for that kind of thing. Try restroing all bios settings to default, take off any overclocks and update and reinstall all drivers for everything, gpu, motherboard, soundcard, monitor, everything. Try getting your machine as much into a 'vanilla' state as possible, and see where you can go from there.