(Excel 2003, SP2) I have imported a .txt file and saved as an .xls file.
Now, at least every 5 seconds, the cursor changes from an arrow to an
hourglass and anything in the formula bar flickers. While it is doing this,
I can't add, delete or change any cells.

I have: copy-paste special value the entire sheet, turned the Autocorrect
off, and selected "Ignore" on any cells with a green triangle.

I have three "personal" macros set up. When I disable the macros, I still
have the
problem.

What is causing this? What can be done to avoid this happening?