Formula for Salary Cap Fantasy Football Team

[ExcelNupmty]

I am looking for a formula for the following spreadsheet:

http://imageshack.us/photo/my-images/214/78616364.jpg/

I am looking for a team of 1 QB, 2 RB, 3 WR, 1 TE, 1 K and 1 DEF. The team must not cost over 100,000. I am looking for the team that will score the most PROJECTED (PROJ) points under the given circumstances.

I am not sure if a formula for this is possible as I am basically an Excel idiot.

Any help is appreciated. Thanks in advance for your help.