I’m kind of a newbie in terms of playing around with my computer’s registry, and I have this huge (and in my opinion, well founded) fear of making make computer FUBAR by playing around with things I shouldn’t. My computer has spyware problems, and I think I’ve found some things that could be spyware. But I’m not sure, so here’s what I found:
-HKEY_LOCAL_MACHINE
-Software
-Perfect Nav
-MidADdle
So if it is spyware, can I just delete these keys and get on with my life? And since I just uninstalled Kazaa from my comp, is it okay if I delete all the entries on HKEY_LOCAL_MACHINE – Software?
Thanks a bunch in advance! 
Mucking about in the registry is dangerous at best and a good way to bork your computer unless you really know what you are after.
To kill spyware I recommend you read through the following:
Basic Spyware, Trojan And Virus Removal
The above is a good start and points you to various free resources to help. I am partial to AdAware and Spybot as a one-two punch but admittedly they miss things on occasion.
If you are still stuck with spyware continue to the more advanced tool known as Hijack This. Read the tutorial below first though before posting your logs to various forums to have the community help you (they are VERY helpful if they think you have made a solid effort at helping yourself first).
HJT Tutorial & LOG File Posting
Interesting, but truthful way to put it.
If you ever decide to screw around in the registry, export a copy just in case you make a tragic error.
Otherwise, your computer could be seriously boned.
Boned and Borked - Attorneys at Law