Windows XP service pack 3 messing up my internet browser

[#1]

I keep getting the yellow shield to download updates to my XP Pro and when i do and it has finished i cannot browse the internet.I cannot connect to anything not even Google  I use Firefox and i know they have had some issues with their latest release and i dont know if Microsoft are deliberately causing this
or it is a fault with the service pack but the only way i can rectify the problem is to use System Restore and then everything is fine again
but before long i will get the annoying little yellow shield that keeps telling me to complete updates etc.Is there any way of removing this reminder without doing the updates as there are obviously problems with this service pack and the latest version of Firefox.

[#2]

it should be OK with Firefox 3.03.
I have two laptops with that combination, I dont down load automatically, I do get the yellow shield, Then I go to the Windows update from the Start, All program, Windows update.  Then click custom, it gives you a list of what is ready for you, - by default all ticked and a box with +.  Click this and it tells you what each update is for.  Unclick those you dont like the look of,  go to top of page and click install, sit back and wait.
Both my machines are OK, most of the updates are security ones.  I dont like MSN so dont download.

[#3]

Its not SP3 and firefox all my pc's have it on with no probs. Have you got Zonealarm as that had a issue with SP3 which stopped the internet. Does it kill the network or just the browser ie can you still run ping 194.119.131.66 or get email?
What is the pc as odd ones had an issue with it and you needed some updates before sp3 so it would be ok. AV can also cause problem it should be disabled while updating to sp3

[#4]

It only appears to affect the browser doesnt stop the internet i just cant go to any address when u say AV is that AVG as that was running when the service pack installed that may be the problem. I have a Dell Dimension4300

[#5]

From memory, it was Dell that had a problem, try updating your Dell drivers