Sdelete may require services or functionality that has not been started when the RunServicesOnce key kicks in.
If you use
regedit, find the key in the left panel, highlight it to see all existing values, right click the right panel, add a new string value, pick a name for your key, and in the data field enter the fully qualified path to your program.
If you use
reg from the command line type
reg add /? for details. Note: the regkey data type should be REG_SZ.
My final hope is to run a batch file(SDOS.BAT) that calls out an executable file(Sdelete.exe)
You may have to run Sdelete.exe directly without the batch wrapper. The cmd processor (required for batch files) may be unable to start this early in the boot cycle.
SDelete needs access to certain files before they are locked by Windows.
Just asking, but if Windows protects files it needs to operate, why are you deleting them?
CYA:
Backup your Registry before proceeding.