I've found through trial and error that disabling the wrong ones doesn't seem to break anything on your system, it will just render certain parts unusable. Internet is probably the most likely one to stop working because there are alot of services that deal with internet. I'd recommend disabling about 5 at a time, write them down, reboot, see what still works. Then go for more. If something breaks, you can always re-enable one of those 5 at a time and see which ones were needed. I do not believe any critical services can be disabled, so it's relatively safe. I did get WinXP to load up in 32mb of RAM once by disabling basically everything except an audio driver and Gigastudio, just to give you an example. The machine booted in about 11 seconds from power-on. So they can make some difference. If you're not using internet, you can disable at least half of the services because many have to do with other computers, IP addresses, file sharing, and security. I'm sure there are some good websites out there on services and what they do, plus there are descriptions in the menu about what they do. I'd go to Start-Run and type SERVICES.MSC to launch the services program (different than the MSCONFIG one). You can also arrange them by what is running just by clicking on the heading Status or Startup type. I have 10 services running right now for my machine which is on the internet and does file sharing, and I think I started with over 30 before disabling stuff. Hope this helps.