cmd line command to kill open files on a server?

Well:
net stop server
will stop the server serrvice and cut off everyone connected.

A quick way to do this is to type the following on a command line:

net stop server & net start server

The above line will both stop and then restart the server service in as quick a time as possible.

You do realize, you'll end up potentially screwing up peoples files if you close open connections...

There isn't a way for me to close a specific file?

Yes I understand that, but there are certain files that need to be altered at midnight and if users have that file open, well it doesnt work :)

myfootsmells

Another thing you could do is script the deletion and creation of the share.  For example:
net share sharename /delete
net share sharename X:\PATH

There are additional commands - run net share on a system to get help for the command.

You might find these interesting:
http://groups.google.com/groups?q=Windows+close+open+files+script&hl=en&lr=&ie=UTF-8&selm=3BB98F58.3B8BDD9E%40hydro.com&rnum=5
also
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=8akio0%24b9l%241%40ssauraab-i-1.production.compuserve.com&rnum=8&prev=/groups%3Fq%3DWindows%2Bclose%2Bopen%2Bfiles%2Bscript%26hl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D8akio0%2524b9l%25241%2540ssauraab-i-1.production.compuserve.com%26rnum%3D8

Try this.. This could be useful....

http://www.sysinternals.com/ntw2k/freeware/pstools.shtml
http://www.sysinternals.com/files/Pstools.zip