Should I restart the machine after quarantining spyware entries?

Yes! You must restart the machine after you have quarantined the spyware as some spyware entries are not quarantined at that time as they may be in use. So, those entries are quarantined properly only after you restart the PC. Spyware Detector itself asks you to restart the PC whenever it finds any such spyware entry.

After restarting machine, open the application and click on Recover button.
This will open the window, check the select all box at the left bottom of that window and click on Delete button this will delete the quarantined entries from your PC.

Sometimes you might have to scan the PC again after this process and delete them again in the same fashion. It is not because we cannot remove them, it is because those are dangerous spyware which keep themselves active until the PC is shutdown, so we again have to track them and delete them.