could I just download the dll file onto a memory stick and drag and drop to replace the version currently residing in the win32 folder?
Not unless you can boot into XP!
If you can boot into Safe Mode that might work - but bear in mind that there are currently at least 4 versions of that file - so you would need to ensure that you have the correctly matched file.
You should be able to boot into the recovery console - assuming that you have the install disk - and restore the file from the CAB archive. But then you may find that it's actually the SP2 or SP3 version you need. Which you may be able to get from another PC via floppy disk - providing you have a floppy drive - and diskette!
However, there should be a backup of the correct file in the \Windows\Servicepackfiles\i386 folders on the C drive - it might be possible to copy that over.
SD