Go into the hardware properties and make sure ur HD is using DMA not pio, via the IDE ATA/ ATAPI Controllers.
If that is already set to DMA, Then try running your pc in safemode with all devices conected over night and see what happens.
Also set your bios to Default before doing this as windows could also be fighting with the Bios which is therefore making it crash. Doubtfull but worth a try
If it runs fine in safemode over night, then reboot as normal not into safemode and then leave it again over night but still @ bios defaults. Also make sure your power settings do not turn the hd's off after a certain time of being idle. Set them to max power settings.
keep us posted
