Excel copy picture truncating chart

One coworker has a chart in Excel. When she uses shift-edit to copy picture as picture, as shown on screen, she gets an error saying the chart is too large & will be truncated. When she then tries to paste it into Powerpoint, the Y axis is distorted (shortened). Copying as a bitmap works, but greatly increases the file size, which is undesirable for emailing.
However, this doesn't happen on anyone else's machine. They can copy picture as picture as shown on screen (exact same chart) just fine.
The only difference I can find is that the others use W98, while the problem machine uses WXP. All use Office 2K. I use W2K & have no problem.
Is there a solution or setting to this problem? Thanks.