Plain text font for txt files

Have a client who has win 2000 on his computer. He accesses lots of standard text files thourgh his browser.

He is running IE 5.5 SP2 and the text for some of those text files comes up as blocks, but not all. we have tried changing the plain textfont in notepad, we have tried it in IE font settings. IT has helped some but the problem still persists. This does not happen on any other machine we have tried. Windows 2000 has been reinstalled from scratch and it does it. We have extracted all the fonts fresh off the windows cd as well.

I have a feeling it has something to do with a setting or a driver. does anyone have anything that can help me on this? Its driving me nuts.

Alon