Checking if software is already installed

[ocoro02]

Hi folks - I had a bit of a search to see if this has been asked before - I guess it must be a common question but can't find anything.

I'm writing software installers and commonly need to check if a package has already been installed. What's the best way of going about this? I'm just simply checking existence of a top level directory for now, but I realise this isn't really good enough. Is there an easy way of querying whether a particular package has been installed without querying the registry?

[weaponx]

Instead of checking for the existence of the folder you should be checking a list of files. What do you have against the registry? I would personally check both. I think you can also use WMI:

http://www.microsoft.com/technet/scriptcen...s.mspx?mfr=true