In a large Excel spreadsheet, I am looking to add a simple timer which will,
when started, put say a 'Y' in a cell for 1 hour. No countdown display or
anything complicated needed.

I've googled and tried a couple from the web (VBA code) but they seem to tie
up the spreadsheet's resources (hourglass spinning etc) while they are
running, which is no good for what I want.

Any suggestions please?

TIA,

V