accessing functions across several programs

Question

Hi! First post here.
I'm looking for some guidelines in a tool I want to develop.

I'm currently working at a helpdesk and I have to access many different programs on different remote machines in order to solve incoming cases. In one specific project I'm working with there's a lot of resetting passwords of users in Active Directory on several domains. What I'm looking for is to create a tool that gets the user I want to change the password of, connects to a remote machine that I supply, opens up the AD, sets a random password to the user and returns the password to me.

I don't know even where to begin. Any suggestions on where to start would be greatly appreciated. I've only covered .NET mainly for the web so this is very new to me.

Thanks for reading!
Cheers