WinXP SP2 - effect on web services and .NET?

My original impression of the WinXP SP2 update was positive. I updated 3
different PCs and everything seemed okay, apart from a minor bug. I
intermitently received a Windows Application Error on startup on one of the
machines. The error was : "The instruction at 0x0045edb0 referenced memory at
0x0000000. The memory could not be written."

This didn't seem to cause a problem until I attempted to install the .NET
Framework v1.1 SP1 update. It didn't install. Worse, I couldn't uninstall the
..NET Framework v1.1, nor could I use System Restore to recover to the time
before I attempted the .NET v1.1 SP1 update. I won't detail all the trials
and tribulations but if you want to read them they are on the
dotnet.framework.setup newsgroup at
http://communities2.microsoft.com/co...b-3d67143600f7

To cut a long story short, by restoring my PC to its pre-WinXP SP2 state, I
noticed that the SP2 update affected the S3SVC and SMTP services. After
installing the update these services would hang on startup - i.e. they show
as "starting" but never actually start. This seems to have been the cause of
the problem with installation of the .NET Framework v1.1 SP1 pack.

Fixing the problem involved restoring the system to its WinXP Pro pre-SP2
state via a Norton Ghost backup. Then unistalling the NET Framework v1.1.
After re-installing WinXP SP2 and noticing that the S3SVC and SMTP services
were stuck on "starting", setting both of these services to Manual startup
and following a reboot I followed the MS Knowledge Base Article - 273639 on
debugging IIS Admin services. On restarting the W3SVC via the debugger,
Norton Firewall registered an access attempt and I set appropriate
permissions. After this I was able to install NET Framework, the SDK and the
SP1 pack for v1.1 successfully.

I don't understand what the problem is with the W3SVC and SMTP after
installing the XP SP2 update, as I disabled the XP Firewall immediately (as I
use Norton's FW). But for some reason SP2 causes both of these services to
hang on startup and require a new set of access permissions for the Norton
Firewall in order to work correctly.

Of course this may not be the root cause of the problem, but just the
work-around that I managed to stumble upon. Whatever, after installing WinXP
SP2 make sure you check that all the services that you thought may be running
still are. Better yet, make sure you have a solid backup of your system
before you even think of doing the upgrade.