Validation

Welcome to OzGrid,

If you want to be able to check constantly as the user enters data in these cells, then you will need to use formulas.

If you rather have it that you can check the cells anytime you want, then you could use a Sub.

In order to use formulas, you could generate a formula for each cell in question doing the following:

Sub GenerateFormulas
     'Range, and worksheet to set formulas
     for each cell in worksheets("Sheet 1").Range("A1:Z10")
          'fill the formula for what you need
          cell.formula = "=if(value, true, false)"
     next cell
end sub

if you just want to check wheneer you want, you can do the following:

Sub CheckCells
     'Range, and worksheet to check
     for each cell in worksheets("Sheet 1").Range("A1:Z10")
          if cell.value = 66 then
                 'display message
          endif
     next cell
end sub

Cell Validation

Depending on how data ends up in the cells I'm not so sure that there is any need to use code (VBA) to perform validation.

If data ends up in a cell by linking or importing then maybe vba code is necessary but if you want to validate values / text etc as you enter then Excel's built in Data Validation should more than suffice.

There are some excellent examples of Data Validation at http://www.ozgrid.com/download/default.htm. Data validation when combined with Dynamic Named Ranges is extremely powerful and could replace vba code of reasonable complexity.

Alternatively you could do a search of the forum looking for postings on the subject....there are lots of postings.