Editing makes file slower

I have one of many spread sheets that has a problem. I am sharing it with a colleague and after receiving it, it opens OK. But as I work with it, editing and adding content everything gets slower and slower. I suspect there is a function that is cycling in the background and it keeps growing in size until my desk top splutters to a crawl and gives up. I have noticed a J in the corner of some of the cells.

Does anyone know what is happening and how to clear and switch off whatever it is? I am using the Excel 2003 Student and Home version.

Am working with it and waiting for it to clog up. Suspect the other party is trying to use a tool they don't know how to "manage". I asked them the same question but was met with blank looks and denials.

A 'J' appears in the left top corner of a cell. Its got something to to do with Web Scripting which is not enabled and the file grows to 25meg. Am trying to attach but its big.

There is no call for any formulas. Its text only. I suspect the other party might have added a tool to add notes but she is not letting on. What happens is that I start working with her sheet, deleting lines, making comments in others, copy and pasting. And whatever it is, kicks in after 20 mins or so and the size of the file grows till it bacomes unmanageable. What I suspect is happening is that there is a command that is cycling.

When I right click the feature that I have noted, it opens a message saying Web Scripting is not enabled on my machine and asks whether I want to turn it on.

I can copy paste the content to a new work book and it works for a time. But after awhile the same thing happens. You mention linked cells. What do you mean by linked cells?

I do have Drop Box installed on my work station. But this file is not being used on drop box nor is the other party using it as far as I am aware.