does GetVolumeInformation do the trick? i think that this does not give the unique hard drive serial number but the volume number, may be good enough.
http://www.news2news.com/vfp/?group=29&function=145~M
>Hi, I need to add more secure to may aplication. How VFP send me, Hard Drive Serial Number.
>Thanks.
Go raibh maith agat
~M
