Nested IF function - What am I doing WRONG?!?!

Hello all,

I'm still learning Excel, and sometimes formulas vex me. I'm trying to meet the following conditions:

- If the date in B4 is after today, the status should show "In Progress"
- If the date in B4 precedes today, the status should show "OVERDUE"
- If the date in B4 precedes today and D4 also says "No" or is blank, the status should show "OVERDUE"
- If the date in B4 precedes today and D4 also says "Yes", the status should show "Complete"

This is the formula I'm using:

=IF($B4>=TODAY(), "In Progress",IF(AND(ISBLANK($D4),"OVERDUE","Complete")))

The first part of the formula works, but the second part produces an error. Can anyone enlighten me as to what I'm doing wrong?




EDIT: Nevermind! I figured it out. I'm using

=IF($B4>=TODAY(),"In Progress",IF(OR(ISBLANK($D4),$D4="No"),"OVERDUE","Complete"))