Spybot is an EXCELLENT program. It is a great FREE scanner, remover program. I highly recommend it. You can download the newest version HERE Save it to the desktop. Double click to install. Be sure that youDO NOT to enable the TeaTimer portion of the program, it frankly is more trouble than it is worth and can interfere with removal of nasty items should the case arrive. Once you have it installed then be sure to update it. Keep it manually updated each week and once it is updated then always remember to do a full scan with it. Once the scan is finished then have it remove any critical items it finds.
Now, as for the difference between SpywareBlaster and Spybot...a lot. SpywareBlaster is a protection program, no scanning involved, just install, update weekly, enable new protections and close the program. Be sure to enable protection for Internet Explorer AND Firefox if you use that browser also. Plus, Enable the Restricted Sites portion of SpywareBlaster too.
When you scan with Spybot for the first time it is likely you will find a lot of items it should remove BUT after that, if you also have SpywareBlaster on the computer the items Spybot will find in it's scans will be much less.
A good antivirus program, firewall, Spybot and SpywareBlaster all work very well together and will help to keep the computer safe.