Happy Friday!

I have a spreadsheet that someone else created with macros, conditional
formatting, etc. I'm trying to help revise it. Can you help with the
following questions:

1. How do I disable a macro?
2. When I try to edit a column that either have a macro or conditional
formatting, I get "run time error 13 type mismatch" - what does this mean?

The column that I am trying to revise has a validation list (say column B)
so if I type number in (column A), column B automatically defaults to "SST"
(a selection from the drop-down list). I need to have that default to
somehing else in the drop-down list say "Green" - how do I do that? I try to
find and replace or auto correct, it does not work, HELP!

Thanks in advance!