This morning I booted up my system and it just wouldn't come on(it just stay at the windows xp loading screen) I rebooted and went through quite a few troubleshooting steps. My system sees the drive but when I try to format or do anything to the drive it makes no progress. I felt the drive and I could feel it spinning but it feels more like it's pumping(or pulsating). I've tried more things then I can list right now, so far I don't think its the motherboard.

(Some of)My system specs are.
Athlon 64 3700+
Asus A8N-Sli premium motherboard
Seagate 160GB barracuda hard drive(ncq)
Windows XP Sp2
2GB of OCZ ram
Geforce 7800gt
and a Seasonic S-12 600watt power supply