Probably most space is being consumed by CSCOpx\log.  To quickly cleanup some logs, you can manuall run the command:

logrot_trunc c:\Progra~1\CSCOpx\log\syslog.log

Assuming this is the correct path on your server.  You can also schedule log rotation to occur on a regular basis to avoid the logs growing past a certain point.  This can be scheduled under Common Services > Server > Admin > Log Rotation.

Might also be a good idea to check if you have debugging turned on under the various modules in LMS to decrease the speed of the log growth by setting the logging to a lower level.