Using Mach3 with Win XP on old MSI motherboard.  Same setup for years without issue.  Hard drive died and replaced.  No mirror copy of it as I should have, but had regular copies of all files.  New drive, reinstalled identical Win XP with slipstream from before.  Mach3 opens, but no power to steppers... red lights on Geckodrive G540. Mach settings (Ports & Pins, Configurations, etc.) are set up exactly as before, because I had backup of personal milling setup, and was able to double check all settings as years ago I took a photo of EVERY page of settings.  Parallel cable is connected directly to motherboard, not a card.  Made sure BIOS was set to EPP, but also tried Normal, Bi-Directional, EPP, ECP, and EPP & ECP to no avail.  I'm sure I'm overlooking something very minor but can't find it.

Any help is appreciated.

Try disabling the G540 Charg Pump feature (switch near 12 pin terminal strip).
If you now get green light and it works then you need to set up the Charge Pump in Mach3 and re-enable the feature on the G540.

Tweakie.

I figured it was something simple I overlooked, after scouring hard drive, forum, and digging through the manual and notes for 3 hours.  That teeny-tiny little hidden switch.  I'll make a note of it in my manual this time.  Everything is good to go now. 

Thank you so much for the help, Tweakie!