Kevin, I use Spy Sweeper for spyware removal and protection along with NOD32 for anti-virus. Over the years I found Norton to be a resource hog that dramatically slowed PC operations. NOD32 is little known among the general population, but very well known among us techies. Neither of the above are free products and well worth the money. I believe both are available now in trial versions. Spybot and Ad-Aware are decent products, but they do not have the capabilities of products like Spy Sweeper. Webroot, makers of Spy Sweeper, also offer a very nice cleanup utility Internet files, cookies, temporary files, etc., called Window Washer.
As a side note, a product like Max Registry Cleaner is very good at cleaning registries and increasing performance. For defraging, use a product like JKDefrag.