I had my first chance to use the new System Restore feature of Windows XP this afternoon. A home networking wizard hosed my DSL modem setup and rendered my Internet connection inoperable. All my attempts to reinstall the drivers failed.
With System Restore (on the Accessories, System part of the Start menu), I could back up my system configuration to the moment before any of those driver installation attempts, to the last autosave at 1:22 a.m. this morning, or to different moments on several different days. If a choice wasn't an autosave, the change was described (for instance, "Driver installation attempt, 3:38 p.m."
I chose to go back to 1:22 a.m., continued the System Restore wizard, and five minutes later I'm back on the Internet with no apparent loss of data. Sometimes, you gotta give those monopolists a hand.