Why wont 0 stay on excel spread sheet?

Get some blue glasses.

The two most likely causes. 1) There is a fan limiter senser/switch mounted somewhere on the furnace plenum. The switch is defective, or possibly needs to be removed, cleaned, and reset, then reinstalled. 2) On some furnaces, there is also a relay that turns the fan on and off. The relay may be ...

mistake, i changed the path by ok now thnx all

It all depends on the gauge of the metal... if its thin enough tin shears with a steady hand will work fine... if its thin use blades with more teeth... if its very thick use blades with less teeth.

If you right click on the sheet tabs at the bottom you should see Unhide as an option. If you have hidden sheets it will be blue, click it and select the sheets to unhide. For the date go to Format Cells and select the date format you require.

You should choose a target cell, lets say B2. click on B2 and type = . then go back to B1 and type /9.1 to copy this formula just drag the cell from the lower left corner.