Hi Sunita,
Ahhh, I see. I thought...
If
vb is not throwing any type of error event, then the best way might be to find a reliable reference in the registry which sql always uses only when installed (maybe a version number, path or licence key), if the reference exists, then you have a pretty good idea that ms sql is on the machine (might work, but not perfect, cause if MS SQL was installed and later incorrectly removed, then the reg item you pick may still exist even though MS SQL has been removed).
Also, make sure that
VB's error handling hasn't been turned off (can't remember how this is done, just remember that there is a way and the writers of Setup1 may have done it).
Regs,
Brian.