Do "power saving" settings in w2k kill DSL/network connections?

[db]

I have dynamic IP addy through DSL, and it seems that if my computer is on and inactive for, say 1 hour, I have lost my "allways on" connection and have to recycle the modem. My monitor does turn off after 15 min., but to my knowledge nothing else "powers off". Do some of the older HDDs power off on their own after a period of no activity even though the software setting is not enabled for power down?