1. Norton System Works !
2. Spybot - Search & Destroy
3. Adobe Photoshop Elements (Cheaper than full PS, and has all the needed features)
4. Adobe Priemier(?)
5. Regedit!
Seriously though, you should be able to make most of the tweaks manually, but TweakXP is a good utility.
6. Fruity Loops - Best Audio Mixer for PC. MIDI Input, VSTi & DXi plugin support, 100s of loops, effects, etc.