Performance problems / 100% CPU load

Performance problems / 100% CPU load

Hi,
I have a very simple sheet with 6 columns and ca 350 rows. No formulae, nothing complicated, just (small) integer numbers and short texts.
Entering data manually works, the browser even buffers a large number of entries before displaying them, but takes half a second or more for each display step (display newly entered number, move focus to next cell, switch alignment of previously entered number from left aligned to right aligned).
Selecting (highlighting) the columns takes at least a minute where the CPU is fully loaded (and the IE window must remain the active window or I can't continue without selecting different cells...), selecting the "sort" entry in the context menu takes ca 10 seconds and sorting the rows takes minutes.
I've seen the same effect on two different PCs, both running Win XP and IE 6.
I'd be happy to share the file and help analyze the issue - I will share it with support at zohosheet dot com after I post this.
Thanks in advance, Klaus