I'm trying to set up 3 different formats:
#1 If a value is less than 800 I want the pattern Green
#2 If this value is between 500 & 200 I want the pattern Yellow
#3 If this value is less than 200 I want the pattern Red

This works for me with Excel 2003.

Condition 1: Cell value is less than 200 Format Red

Condition 2: Cell value is less than 500 Format Yellow

Condition 3: Cell value is less than 800 Format Green

Depending on the need, "less than or equal to" might be called for instead
in one or more of these.

Modify to suit.