You need ONE firewall and ONE anti-virus program running on your PC. (Having two of either can lead to serious conflicts, which can cause major problems). Additionally, you should have provision for dealing with spyware. (Because anti-spyware programs are usually 'run on demand' rather than 'run in background', you can have as many as you like because you'll only run one at a time, so they won't conflict).
Norton products are notorious for slowing computers down, so getting rid of Norton (irrespective of what you use instead) is always a good idea.
Spyware Doctor provides you with one anti-spyware program. As stated, you can have more if you like. (Some threats seem to get picked up by one program but not by another). The most popular free anti-spyware programs are Adaware and SpyBot:
http://www.lavasoftusa.com/products/ad_aware_f ree.php
http://www.safer-networking.org/en/spybotsd/in dex.html
AVG 7.5 covers your anti-virus requirements. (It's the most popular free program, with Avast! as runner up).
My only concern is that you don't seem to have a functioning firewall. You've got rid of Norton (good move) and disabled the Windows firewall (also a good move because it's not highly rated) but I can't see anything in your post that suggests that there's any firewall now running.
The most popular free firewall is Zone alarm Free Edition:
http://www.zonealarm.com/store/content/catalog /products/sku_list_za.jsp
Use EITHER Zone Alarm OR Comodo (which is also popular), NOT BOTH:
22:30 Fri 07th Mar 2008