1. If you see two CPUs and your processor is indeed hyperthreading, it's ok; my cpu is P4HT2.60 and listed twice in the Device Manager.
2. If you see two VGAs and you cannot uninstall either of them then one must be the onboard video that can only be disabled thru Bios.
3. If I were you, I'd rig a bare-bones h/w configuration (mobo, cpu, ram, vga, floppy, 1 X hdd, 1 X cd, fans, psu) and start running it (if there's vga onboard, even better - you can skip the vga at the most basic setup). The first thing would be to run the
Windows Memory Diagnostic utility and the HDD diagnostic utility (downloadable from the hdd manufacturer's site). These are bootable and run under DOS (what a blessing...). It is important that you get into your Bios and confirm all settings are correct and correspond to your current setup every time (you can reset CMOS before starting this endeavor). Also, make sure you have a system floppy handy, along with sata drivers for your hdd (if it's plugged on the sata controller). After having run all the tests (push the envelope a bit; check the memory for some time), and having verified that everything is OK, then I'd start building up, one device at a time. If at some point Windows stop booting normally, then the culprit is revealed. If Windows cannot boot normally even at bare-bones, then a repair installation can be carried out (and this will leave the documents intact).
Hope these help, post back! :-)