Cannot Completely Download Service Pack 2

I am running Windows XP on an E-machines T2385. I had previously loaded the MS Plus! Superpack for XP so that I could utilize Media Player 10 and Movie Maker 2. After several unrelated problems I had to perform a system restore, which was successful. I recently tried to load the Plus! software again and experienced some permissions problems. I was advised by MS to download and use download the Microsoft Installer Clean-up Utility. I was then able to load Disk "1" of the Plus! XP Superpack with no problem. In attempting to load Disk "2" (Digital Media version; w/Media Player 10 and Movie Maker 2 w/ add-ons) I was again prompted to download Movie maker 2 from the internet. Once again it was only available as a download WITH Service Pack 2. I attempted to download SP2, and this time it appeared to proceed smoothly. However, once I got about half way through (as indicated by the status bar) I received the following message pop-up:

"Service Pack 2 Download: Access Denied. OK."

I clicked OK and the following pop-up appeared:

"Service Pack 2 Set-Up Error: Service Pack 2 installation did not complete. Select 'OK' to undo the changes that have been made. OK"

I clicked OK, and a pop-up indicated that various components of the SP2 set-up were being undone, and files erased and deleted. At the conclusion of the removal of SP2 files I received the following pop-up:

"Service Pack 2 Set-up Error: Service Pack 2 installation did not complete. Windows XP has been partially updated and may not work properly."

I was then prompted to restart my computer to put any of the changes into effect.
window indicating that a critical update was available. I'm not certain if the update was simply the latest and greatest or somehow related to the problem at hand... but then when I click on the download option/update referenced it proceeds to a point and then gives me an error message stating that certain files needed to be updated before the download could be successful.

This is becoming frustrating. I would think that downloading SP2 with WXP would be an easy thing to do... but apparently not. Please help! Thanks...