VSS or some Version Control Software

We’ve ASP application which incorporates MSSQL-2000, IIS5, COM/COM+, Seagate Crystal Report running on w2k server.

Now due to expansion we are facing difficulties in managing files on our development servers. As some times the same file is being used by different developers. Other time they change a file which wasn’t required.

So we want to implement some kind of Version Control software. So that every file gets locked. & only the appropriate files are being allowed for change. (Don’t tell me NTFS permissions)

For that we tried Visual Source Safe (from MS-VS6). But its not working. or may be we don’t know better how to configure / use it.

Tell me is there a way to do it on W2K. or is there any other software for the same issue?