Step 1: Start the System Configuration Utility
Start - Run - msconfig-ok
Step 2: Configure Selective Startup Options:
General Tab: Clear "Process System INI file", clear Process WIN INI file, clear Load Startup Items but do NOT clear Load System Services
Services Tab: Select "Hide All Microsoft Services", then select "Disable All" then OK.
Restart when prompted.
Install XP SP3 on the reboot (click to select "Dont Show this message...etc)
after install completes, run msconfig again and select Normal Startup