Programmatic Password entry for RUNAS WI

Under WIN NT I used a MS ultility called SU which allowed me to drive a program as another user. This had the advantage of allowing ACCESS databases on restricted shares to be opened (lock file) as well as ship files to the share, or have a program place files to a locally restricted site. SU does not work on WIN 2000. So how can I get VB to drive it & supply the coded password??