I can't seem to hit the c.f.o in the helmet, i tried 3 times last night and failed eventually i died, first time in cashbot hq too.
Is their any tips on how to hit him ?

You mean when he's wearing a safe as a helmet and you're trying to knock it off with another safe? Sometimes it helps to swing your crane (with a safe on the end already) all the way forward, all the way back, then all the way forward again, then release. When you release, you want it to be at the very end of your swing--if you release too soon, it won't knock the safe off (but then again, releasing too late doesn't work either). Just keep practicing at it. I couldn't get it at first (and sometimes I still can't) without the forward/back/forward thing, which is really slow, but seems to help me a lot.

What TerrKan said...
I could be wrong, but I think hitting his helmet a little off to the side (not right in his face) seems to work better and like TerrKan said, if you get that back and forth thing going (as opposed to round and round ) if you let it go on the upswing away from you with the boom out, it hits his helmet in an upward arc.
Sometimes it seems like it's superglued on huh?

The above is great advice.
One thing I will add, though. When I had my old computer, bought in 2001, I could rarely get his helmet off. When I bought a new computer last year, it became child's play to bump it off (mostly anyway!).
So, if you are really struggling and have an old computer, it might not be all your fault

It takes a skill to hit it just right....Lord knows it takes a couple times sometimes to get it right....sorry about your loss just keep trying, you'll get it