Use of MouseDown - complete idiot needs help

[Rob Rob]

Here's the challenge:
I'm confident in and around a spreadsheet, but when it comes to VB and macros, I'm hopelessly inexperienced - so any explanations offered need to spell out where to put code, in which modules, what to name them etc. If I don't uderstand, then you failed miserably to convey what you know to be ridiculously simple! :)

OK - the meat:
I have an Excel spreadsheet that uses circular references to converge results and has calculation set to MANUAL, and iterations set to ONE for every time I calculate or hit F9. I would like to have a button on my spreadsheet that when pressed and held, it keeps calculating the sheet (like holding down F9), until I release the mouse.

How's it done? XL's VBA help file on using 'mousedown' (and up) does not take account of my vast ignorance of even the most basic of knowledge about modules and class mods and declarations etc etc. Maybe there's some other way to mouse listener method?

Thanks for any suggestions