Using Win 7 home premium here, it was an upgrade on Vista 32bit. SO FAR no trouble at all, my pc is a Dell 5150, 3,2GHZ p4, 3GB DDR 2, ATI X1650. Very ordinary.
Your problems sound like faulty ram, or a few failing sectors on the C drive.
If the ram has faults you would normally get past the bios screen, then see a STOP error. Windows would not load at all.
Win7 includes most of the drivers for the devices most people use, you only need to install drivers for things such as scanners, printers, and very new graphic cards.
The free program 'drivereasy' finds most drivers for you.
But without knowing any more, it sounds like a hardware problem to me.