Thanks for your post.
If you just want to start over, and you're happy to lose all the information and configuration you currently have, then the quickest way is to get rid of the database.
Stop the "SQL Monitor 2 Base Monitor" service, and then drop the DB you were using for Monitor. You can then quickly re-run the setup program and create a new repository DB and configure it once again.
You can read some performance guidelines in the second half of this page
which may be useful.