Help with FTP password

Guys. I'm in a tough spot. My friend recently died and he was the site admin for our php-based site. While I was an Admin there as well, he had complete control of everything and his parents host our site.

Well...WAY too many people who don't need it, have access to our FTP directory. Basically this directory holds all our phpBB stuff, phpmyadmin stuff, pics, files, and miscellaneous stuff.

I'll be going down to play with the server this weekend and want to change the password for our FTP. But...I HAVE NOT A CLUE how to do this. Can someone offer some advice? I'd gladly take a link to a place that explains it...but I have NO clue about what is required, so I'd need some DUMMY explaination.

So, any help is appreciated!!

Is it a windows or Linux server. All you need to do is change the login password for that user.

Windows => go into 'User Manager for Domains' and then find the user and change password
Linux => at terminal window type 'passwd username' and then enter the password for the user

I'm positive its windows. So, he had the directory stored someone on the server and when we go to FTP to that directory it prompts for username pass. (we all have the same one) So, basically in User Manager I'll just look for that username and change it? Sounds easy!