Look for "The Scala Programming Language". I believe its with the "T" in the alphabet.
This is a windows versioning thing, so you have to make sure windows installer knows it was deleted using add/remove programs. You may need to "repair" before you can uninstall.
If you have issues, you can probably expand the zip in the previous install location to temporarily trick it.
Note: unfortunately, windows always requires an uninstall between 2.x releases....