change background color if weekend (saturday and sunday)

Hello,

I have the following situation:

2 excel workbooks
- One contains something like a calendar (31 rows B1 to B31): the cells are formated like "dddd" giving the name of the day for each day in the month.

- The other workbook contains a sheet with 31 cells in line (C15 to AG15) formated as "d" that get information from the first workbook

Example for C15 formula:
=[calendar.xls]Sheet2!$B$1
where B1 from calendar shows the name of the day for 01.10.2009.. and so on for all days in a month.

How can I change the background color of the rows 15 to 67 for if the cells or row 15 are the weekend days (in the second workbook)? The values shown on row 15 are dates from the calendar workbook formated as "d" so it only shows numbers.

I tried using conditional formating with values:
cell value is eqal to =Text($C$15, "dd.mm.yyyy")
but I get formula error. I also tried several other formulas like ="Sun" but nothing happens. Either I don't know how to use conditional formating or the concept I try to use is wrong.

Also even if I managed (which I haven't) to color the cells on row 15 which corespond to weekends, how can I make it color all the cells in those columns on every row till 67?

If my problem is not clear please let me know and I will try to be more precise.

Just extending zbor's post...

Highlight the range C15:AG67 (select C15 first) and apply a Custom Format rule of:

=WEEKDAY(C$15;2)>5
set format

This will apply the Format to the entire range simultaneously with each column looking to the appropriate value in row 15.