Help please vr6 wont start

First off hi to everyone nice forum you have here,

now i need a bit of help please my friend has a k reg vr6 and rang me up yesterday to say his car wouldnt start and was jut clicking when he turned the key so i just thought easy the starter is knackered,when i got there the clicking he could hear was a relay and not the starter so i followed the wire up to some kind of relay box that is under the coolant header tank,then i found that the big fuse on the front of it had blown i thought great so changed the fuse but it still wouldnt turn over anyway my friend said he saw smoke come from round where this box is so i pressume this box is fried.

Can anyone tell me what this box is and what it does please as i am pretty sure this is the problem

Thanks biggie944

here is a pic showing the location of it:

http://i66.photobucket.com/albums/h249/biggie944/vr61.jpg

thanks again