Using XL 2000

I have a worksheet which contains 10 columns A:J and over 500 lines.
The data in each cell in the Column range E:J contains either a TRUE or FALSE.

Row 1 contains header labels for each column.

Im looking for a routine to loop through each column, per line and where a
TRUE exists in that column, and ( where more than one TRUE is found)
concatenate the label name in to column K of the same row being checked.

Hope this makes sense.
Ideas appreciated. Thanks, Paul