Verify cell content BEFORE the cell is left or before some other cell is selected

[Tobias71]

I need to be able to perform an error check of the value that has been inserted into a cell.
But the Worksheet_Change method does not help me because if it detects that the value is invalid, then I need to update the cell value to some standard value.
But this I cannot do because I already have left the cell by mouseclick or tab or so... therefore in the case of detecting invalid user input, the standard value gets written into the wrong cell (the one that is selected after the "trouble" cell has been left).

Can anybody help me on this?

Thanks.

[arlu1201]

Thanks for providing the solution.