This morning, when I got up and restarted the computer, I noticed that all of a sudden all the external devices that were using HD in them were not working.

1) Western Digital 250 GB External HD
2) Seagate 200 GB External HD
3) Zen Creative 30GB Player

I do remember that yesterday evening:
a) I set my computer up for disk defrag (secondary drive F)
b) From Control Panel -> Administrative Tools -> Services I disabled couple of services. (Which I enabled today just incase they were the one causing problem.)

When I use non HD based device such as Web Cam or anything else, it works just fine.

Any idea on what is going on how how to fix this?

Thank you for the help.