Excel 2007 : Weird looking #'s

[stevetothink]

I've noticed that a particular excel file is acting strange. In addition to not being able to reliably group or delete cells, numbers are starting to appear wobbly. Take a look at the attached screen shot to see what I mean. The #'s are curvey...for a lack of a better term.

Any ideas what causes this and how to fix it?

Thanks,
Steve

[royUK]

Attach the workbook not an image