boxes in hotmail/yahoo mail

[maidencailin]

I'm haveing an issue with IE on Windows XP sp1.

When the user goes to read webmail from either hotmail or yahoo, he gets rows of boxes were the text of the email should be.

I've tried the following without success:

Re-installing IE from inf file.
Making sure he had current MS updates.
Running virus and adaware scans.
Updating video driver.

I'm not sure what else to do- any ideas?

thanks