Finding the word OK in a cell

Hello,

I would like to set a background color of a cell if the cell contains OK. The data in the cell could look like:

1.2.3.OK
1.OK
2.OK
2.3.5.OK
1.NOK
2.3.4.NOK
....

So, if the cell contains OK, set it blue. If it contains NOK, set red. The other numbers and dots in the cell should not affect the background color.

/Peter