We upgraded one system by downloading SP2 from the Internet. It installed OK and I optimized the internal firewall and auto-update selections.
Restarted the machine and it took awhile but all hell broke loose. Could not change the url in the ie address, icons didn't seem to work and other little things were astray. Started up trojan hunter and when the sign-on window appeared because trojan hunter was taking more time to execute than expected we could not enter our pass word to get back on.
To make a long story short we powered off the machine and let it set for a few seconds then powered up....everything worked OK. Been using it for a day now and so far so good???? Very strange but I have no idea what corrected a really bad mess.
maybe on that boot it didn't adjust the settings correctly, and when you restarted XP automatically fixed it
XP tends to replace files and change settings if they're not the original, even if you don't know it