Slow startup, slow responce.

Question

i have 5 to 6 minute boots times and software is extremely slow to load. Running XP Media Center edition, all software set not to load on start up by msconfig, except for norton. I have ran full HDD defrag, upgraded to 2gb ram. Task manager shows what ever my current task is as using most of the processor time. HDD light seems to stay on constantly durring boot. Have done full scan using norton and "spy-bot search and distroy".