Trouble Downloading Windows XP and Explorer Updates

I am running the Windows XP Home Edition with SP2. Recently, whenever I try
to run an update to the program. The machine locks-up. This happens with
manual or automatic updates. The same thing happens when I try to update
Explorer. I have no trouble accessing the Microsoft Website, or other
websites. I can also update other programs (i.e. MS Office 2003
Applications). I have tried reinstalling Windows, no help. I have also
tried running the “scannow� program, no help.

The computer will also lock-up when I try to shut down. It gets past the
“updating files� section of shut down, then locks up when the display
indicates “Shutting Down�.