Millenium Edition Install w/out losing data

I am working on a customers PC with ME installed. The problem it has is with an iosubsys driver corruption or low memory. I have tried countless things trying to alleviate the error based on KB articles and web searches.
The last option is a OS re-install. However, there is much data that the customer doesn’t wish to lose.
Is it possible to re-install ME without losing the data?
I have started setup but stopped when it wanted to copy files for setup.
Any help would be appreciated.
Thanks