Today I did a defragmentation on my hard drive. When I reboot the computer I get a BIOS message saying (Pri Master Hard Disk: S.M.A.R.T. Capable and Status BAD, Backup and Replace), it tells me to press F1 to resume. When I press F1, my OS windows tries to come up, but instead it will shut off the computer

. Any advice would be appreciated.
My Computer: ASUS T2-P
Motherboard: P4P8T
Intel Pentium 4 2.8GHz
Memory: 2x512MB PC3200 DDR 400MHz
Hard Disk: WDC WD2000JB-00EVA0
OS: Windows XP (thinking of switching to linux)