If it still hangs in the Recovery Environment, which is Vista's replacement for XP's Recovery Console, then your hard disk may be on the verge of failing. I would suggest running a disk diagnostic utility. Most disk vendors have these for free.
www.seagate.com www.maxtor.com www.westerndigital.com www.quantum.com www.fujitsu.com For example:
Seagate
http://www.seagate.com/www/en-us/support/downloads/seatoolsWestern Digital
http://support.wdc.com/product/download.asp?lang=enThe diagnostic tools are usually going to have to be written to a floppy disk. If you don't have a floppy drive available (even a cheap USB one) or cannot boot to one, then you could try the diagnostic tools on The Ultimate Boot CD:
http://www.ultimatebootcd.com/
