I hope I can explain this ok!

Worksheet A is laid out as:

ID Task1 Task2 Task3 Task4
1 dd/mm/yy dd/mm/yy dd/mm/yy dd/mm/yy
2 dd/mm/yy dd/mm/yy dd/mm/yy dd/mm/yy
3 dd/mm/yy dd/mm/yy dd/mm/yy dd/mm/yy

etc

Worksheet B is laid out as:
ID Task1 Task2 Task3 Task4
1 complete on hold not started not started
2 complete complete complete not started
3 not started not started not started not started

etc

Not everything on Worksheet B can be found on Worksheet A and vice versa

What I need to do:
Is the ID on A found in B?
If yes, look along the row and where something is 'complete' on B, set the
corresponding cell on A as Blue interior, White text.
Otherwise, do nothing

In the example above, cells B2, B3, C3, and D3, would all be Blue/White. The
cell contents of A cannot be overwritten. Worksheet B is deleted once the
macro has finished running as it is just a temporary data store for doing
other background functions.

I have Chip Pearson's (thanks Chip!) fabulous modColorFunctions installed as
I've used it elsewhere in this workbook if that is of use here.

Thanks in advance for any help, all comments gratefully received.

Louise