I have a bit of code I have used for a couple years now:

******************
** zGetHDDSerial
**
**	returns the last 6 digits of the HDD serial number.
LOCAL lcCurDrive, lcHDD, lcValue1
lcCurDrive=SUBSTR(SYS(5),1,1) && return current hard drive letter 'c'

**	return the hard drive serial number
ofs=create('scripting.filesystemobject')
lcHDD=ALLTRIM(STR(abs(ofs.drives(lcCurDrive).serialnumber)))
**	get the last 6 digits or pad with '0' if less than 6.
IF LEN(lcHDD)<6
	lcHDD=PADR(lcHDD,6,'0')
ELSE
	lcHDD=UPPER(SUBSTR(lcHDD,(LEN(lcHDD)-5),6))
ENDIF
return lcHDD

It has served me will till now, all at once I have several users who are all on xp home complaining. It no longer works, instead of returning the Hard Drive serial number, it returns a false (.f.)

I did a little research and found that this runs as an anonymous user in windows. I assume some security patch or something like that is responsible.

Does anyone have any ideas on how to combat this? I'm in a bit of a pinch since the registration of the product depends on this.