I would run a HD diagnostic from the manufacturer's web site. HD lite on constantly may indicate retries. It could be a warning the drive may fail soon. Try to save your data even before running the diagnostic would be my advice.
My Computer
Computer Manufacturer/Model Number
HP Media Center
OS
Windows 7 32 bit
CPU
AMD 5200+ dual core
Memory
2 GB
Graphics Card(s)
NVidia GeForce 6150SE 128 MB
Monitor(s) Displays
CRT
Screen Resolution
1280x1024
Hard Drives
500 GB Sata internal :
SIIG USB 3.0 docking stations w/WD Caviar Black 6 Gb/s drives