IE Hang when resuming SP2 update

I'm working in XP, SP1. I began a successful update to SP2, but I had to
interrupt it and turn off the computer after downloading only a couple MB.

Now when I come back to the Windows Update page, if I click on the Express
Install, Custom Install, or View Inst History, the Internet Explorer window
will hang and never change to anything new, even if I wait for half an hour.
Meanwhile, Task Manager shows occasional CPU activity in IExplorer, but
nothing else.

Clicking on other options in the Update window (Settings, Admin Options)
seems to work OK (which is how I can type this!).

This is preventing me from updating anything. Is there a way around this?