It really is a simple process, you are reinstalling Desktop Manager on your PC again, withOUT the Redirector option (which is where the junk emails are coming from). You are not messing with the OS on your BB.
Removing the Service Books as instructed will cause you no grief either.
after ALL this, if you see that you are getting duplicate GMail of everything you send from the BB, read this:
http://www.blackberryforums.com/gene...-handheld.html
Good luck.