I recently got to the point of needing to re-install Windows XP on my laptop. The base OEM install is XP Home SP1-and-a-bit, and thereafter I added SP2 (the downloaded network-install distribution) and ran Microsoft Update to get all new post-SP2 patches. In addition to the criticals, I installed Media Player 10 and .NET Framework 2.0, and only then did I get down to personalizing my system.
One of my first actions was to change the IE homepage to http://www.google.co.uk
but to my dismay, the change just wouldn't stick. A number of attmepts, setting it in different locations, but it remained stuck on uk.msn.com (possibly my worst nightmare). I even had a go at it in the Registry, but was prevented with an Access Denied message! (This was as an Administrator-level user)
I found that I was able to make the change only by rebooting in Safe Mode. It was the same story with my attempts to modify the Windows HOSTS file: only possible in Safe Mode. Now, at this point I had installed no other software except ZoneAlarm, and I've discounted this as the issue persists with ZA disabled. I'm behind a secure router/firewall, I didn't connect to any websites other than Windows Update and Microsoft Update (and MSN, briefly), and I overwrote the MBR when I reinstalled, so surely it can't be malware. There was nothing suspicious in the HOSTS file - just the loopback entry - and MSN, for all its ills, isn't a phishing or malware site to my knowledge.
My only conclusion was that Windows is actually protecting itself, and quite robustly at that. I'm a bit confused because I've run SP2 since its release (and kept up-to-date with later patches) but never faced these restrictions before.
Can anyone clear this up for me? If this is down to new Windows security functionality, is there a web page with more information about it? I'm keen to know what other restrictions I might run into, and whether there's any easy way to control them.
Thanks in advance.