Firstly: I would not apply this to the WHOLE row as XL2007 has 16,384
columns
Second: why do you speak of 'column 4' rather than 'column D'?
Third: here is how to do what you asked

Select A1:K10
Use Home | Conditional Formatting | New Rules | "Use a formula ....."
In dialog the formula to use is =$D1=100 (or =$D1=100, as preferred) and
format as required
Note the 1 refers to row 1, so if you are using another starting row, adjust
as needed. The $ is essential for your purpose.

Note you can now use Conditional Formatting | Manages Rules and in the new
dialog you can specify the range to which the rule applies

best wishes
--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"Trevor Stone" wrote in message
...
Hi All,

Is it possible to conditionally format the fill color for an entire
row based on a cell reference?

For instance,

Columns 1,2,and 3 are text but column 4 is a number. I'd like to fill
the whole row blue if the number in that row equals 100.

Then I think I can use the painter to copy the formatting to the rest
of the sheet.

Any ideas would be great.

Thanks,

Trevor