Windows 2000 does NOT support BIOS initiated APM time-outs.

If Control Panel / Power Options has Advanced Power Management enabled, and your BIOS is configured to suspend your computer with a time-out that is less than you configured in Power Options, you won't be abled to resume, since it was a BIOS initiated Standby.

Alter either the Power Options, BIOS, or both, so the the Power Options is a shorter interval.