when I was listening to music using WMP, my computer suddenly restart and
shown this messenge: Reboot and select proper boot device or insert boot
media in selected boot device

I shut down my computer and turn it on again, then I can log in the windows
However, after 1 or 2 minutes the computer restart again and the same
messenge appears...

I have the same problem yesterday but then I use the windows recovery
console to repair the system and it works fine.

I just wonder why the same problem keep occuring? Is that virues or my hard
disk is damaged?

and
I would suspect that you are about to loose your harddrive.. If you
know what harddrive you have and model then go to the manufacture's
website and download the diagnostic utillity program. Let it run a
diagnostics on your drive and it may actually be able to repair it.

Keep in mind that no one knows their own products better than the
people that build it...so be leary about using 3rd party repair
programs. Also most retail versions of HDD carry a 3 year warranty
and the only way to get that RMA is through the manufacturer