Help needed with conditional formatting

Hi Everyone, this is my first post on this excellent forum and I'd really appreciate your help.

I run a small target shooting club in the West Midlands and I'm presently writing a spreadsheet on which to record competition results. It's been a long and slow process, based mainly on trial and error. However, there is one particular problem that's got me going round in circles.

One of our competitions is based on 15 rounds throughout the year, but only the best 10 scores count.I have a range of cells recording the scores for each competitor, but some will be blank if a competitor couldn't make a particular round. I've managed to find a formula to give me a total score which doesn't include the lowest score if they do 11, rounds, the lowest 2 scores if they do 12 rounds, and so on up to 15 rounds.

What I'd like to do next is conditionally format those cells where the score is not included in the total. Another problem is that a competitor might have the same score for more than 1 round, Say, if a competitor has completed 11 rounds then if the worst score is 15 then that will be the one to be excluded to give the 10 best scores. However, its highly likely that the competitor may have other scores of 15 but I only want to drop one of them.

My head really hurts and any help would be brilliant.
PS. Am using 2007

I think it would help if you post your current sheet so we can work with the existing formulae.

Thanks for replying hectop but it would be a bit awkward to post the sheet at the moment because it contains competitors names and to delete or change them would corrupt the lookup files.