XP SP1 upgrade problems

Dimension 8300.

After printing the instructions from the Dell OS reinstall page, I reinstalled Windows from the brown OS Reinstallation CD to XP Home SP 1.  It will boot to desktop.

I need help updating it to current version of XP.  Windows Update will not work unless you are using latest SP.  The MS page for SP 3 says I need SP1a or SP2 to use it.  The page to go from SP1 to SP1a downloads the installer program but when I run it the "server is not responding" message appears and directs me to no a longer present web page to download a different install process.  The page to update to SP 2 is "not for a single computer" but intended for network professionals updating multiple PCs across a network.  I have spent hours bouncing around Microsoft web pages to no avail.

Running XP SP1 with IE6 makes it virtually impossible to do anything.  Windows Update won't work, AVG won't install, can't even download Avast.  This desktop was really about my fastest and most reliable PC until it got bit with a bad virus a week ago.  I thought reinstalling the OS would be the answer, but it's nothing but a time-consuming pain.

How do I get this mess straigtened out folks?

Edit: Service Tag removed because it can be used to personally identify you.