Here is my situation:
I have inherited an SVN server (using svnserve only on Win 2008 R2) with a small hard disk and a repository without a specified name. It's path is C:\svn\repos. I would rather not change anything about it if possible, and the disk is fine for that project.
Another group wants a new repository created on this server. I am getting a new hard disk added.
Can I just go to D:, create a folder called D:\svn\repos\Project2, cd\svn\repos\Project2, and then use the svnadmin create command to create their new repository?
We use TortoiseSVN as a client if that matters...
It depends.
If you're running svnserve with the -r parameter, then svnserve will only serve repositories which are immediate child directories of the directory specified by that parameter.
If you do not use the -r parameter, then you can place the repositories anywhere, as you have to specify the full path to the repository on the server.
See the manual for documentation of the various ways svnserve can be invoked.