Hi
I have three PCs, all kept up-to-date and in 'good shape' (OSs clean and stable) - Windows Update has always been important for me - not least the security fixes - and my PCs have always behaved perfectly normally (as they should) to all Win XP SP2 updates previously.
However, XP (Home & Pro) SP2 doesn't 'like' SP3 and Microsoft are fully aware of that. I haven't looked at the beta testing but I would suggest that Microsoft will have to patch SP3 & re-release, fast.
Many people are experiencing moderate to severe problems with this update and it's not a simple issue. The issues vary from machine to machine (and install to install) and whilst the bickering between antivirus Companies is in full flow, they should take an out-of-the-box PC and test SP3 on a SP2 machine!
I would certainly agree with the previous poster who suggested making an entire image copy of the hard-drive and be in a state ready to format, if necessary i.e. all critical data stored on another drive or removable media. If you have not made an entire hard-drive copy, my suggestion would be to wait to install XP SP3.
I was careful to read the Microsoft criteria for prerequisites - all were met in all three scenarios below.
Unfortunately I didn't take my own advice (no full HDD copy was made) for my laptop and I installed SP3 - all non-essential software & services were disabled and all running software was closed, including McAfee (disabled in start-up, msconfig) and verified. Thankfully I haven't lost data or suffered any serious issues but I learned by that mistake. That laptop cannot now run IE7 (v 7.0.5730.13) normally - only with "all add-ons disabled", FireFox and others browsers do the trick ;-) IE8 is not a logical option for me, given the fairly disastrous SP3 release.
I uninstalled some ActiveXs and modified fifty-eight registry keys and it is manageable and usable. Flash Player cannot run as it causes an IE7 fault and fails to respond - Task Manager is then the only way to close IE by which time CPU usage is shown at 100% (though I know that's not a good indicator of true CPU usage). Disabling add-ons permanently doesn't work either, just to make the story even more bizarre. The laptop is AMD running XP Home, SP2 originally.
I should also say that no Symantec products have ever been installed on the laptop.
[Back-up of the registry is critical - Stay away from it if you don't know what you're doing? Use of programs to 'clean' or 'defrag' the registry is a poor choice, in my opinion.]
My second PC (Pentium III, XP Pro SP2 originally) was copied (the entire C drive to a second internal IDE drive; the OS is running on two SATA HDDs) and Norton Internet Security was disabled on start-up and confirmed as "stopped" before installing SP3 via windowsupdate.com. I had disabled all add-ons individually in IE7 as a precaution.
The registry was a mess. It was 10% larger than before the install! The PC was very sluggish and, again, IE7 failed to operate correctly. I couldn't face looking at the registry in detail. I uninstalled SP3 and IE7 and re-installed IE7 and then SP3 (as suggested) - no difference. Flash Player causes 100% CPU usage according to Task Manager and IE7 fails to respond in any way. I am convinced that Flash Player is not at fault here.
I reinstated the HDD copy which worked like a dream and then began again - closing ALL non-Microsoft services and software. SP3 installed, slowly, and I had hopes. No. The registry was still increased in size but that wasn't the problem this time as the PC failed to recognise some drivers ::shrugs:: and the system was so unmanageable that I just restored the same, good, back-up of the HDD. All's well there as SP2 is still running. It will see SP3 when Microsoft has a modified version available for download.
My third PC (Pentium IV, XP Pro SP2 originally) was due for a format and, running 3 IDE HDDs) I made a back-up of the C drive i.e. drive copy (just in case) and proceeded to format it. XP Pro SP2 installed perfectly from CD and all was well. NOTE: I did not install ANY software or additional drivers before going directly for the automated Windows Update site download of XP SP3. The machine was almost unusable and required me to format and begin again - this time staying with SP2
My point is that whilst the large Companies bicker about who is to blame, there are fundamental flaws in SP3 and I have no doubt whatsoever that Microsoft support have been inundated with requests for assistance. There is no doubt in my mind that SP3 was released too early and that beta testing must have been positive enough for Microsoft to release but that beta testing was not sufficiently rigorous - the results on any given PC cannot be determined, or predicted, and Microsoft need to look very closely at their release before allowing (and promoting) its download by users who aren't au fait with computers.
Uninstalling doesn't work well at all - the reg keys aren't all removed and the system affected is unlikely to operate normally (according to my experiences, friends and family). 'System Restore' can't recover a PC after a Service Pack upgrade of this order - a fact that most people are unaware of
Time for Microsoft to look very closely at SP3 methinks.
I should finally add that no software firewall or AV software was running on any of the three machines above when installing SP3 - I disable Windows Firewall, of course ;-)
Again, my advice: make an entire hard-drive copy before starting the SP3 install if you insist on installing it now and certainly make sure you fulfil the Microsoft prerequisites and finally, good luck! :-)
Karl