My father-in-law’s PC has gone screwy again. Sometimes it just happens.  He doesn’t deliberately make configuration changes, although he did recently buy a new digital camera and the installation CD added a lot of third party software that I would have managed without.  I would consider him to be a “normal” Windows user: he uses the PC for Internet (web) access, e-mail, the odd letter, home finances, some family history research and digital photography; he also pays for a McAfee subscription which should keep him safe from some of the badness out there on the ‘net – except that, a couple of nights back, McAfee updated itself and since then something has been “wrong” with the PC.

Actually, I don’t think I’ve ever seen a PC with a networking stack that was so badly “wrong”. Not having been there when the McAfee update took place, I don’t know what messages it displayed but from looking at the event log after a very slow boot, the DHCP client service shut down because “a system call that should never fail has failed”. Then, after a few minutes of waiting, various services failed because of missing dependencies (including, critically for Internet access using his ADSL modem, the Remote Access Connection Manager service). Removing all McAfee software didn’t help. Neither did restoring the IP stack to its default state with netsh int ip reset (see Microsoft knowledge base article 299357).

It was one of his friends that suggested the answer – what about System Restore?  I’d never previously used this feature in Windows XP but it was a godsend.  I restored the system to the state it had been in before the McAfee update and rebooted (see Microsoft knowledge base article 306084).  The boot up sequence was back to normal, the Internet connection was working again and all I needed to do was remove and reinstall the McAfee software.  Which meant that I did get to spend at least part of my Sunday afternoon in the park with my wife and kids.  Result.