[H] Converting MBR to GPT

[Thane Sherrington]

So I have a machine that has a 2TB drive, and I'm putting a 4TB in it.  
It's Win7 x64, so it works fine, but when I clone, I only get a 2TB 
partition (of course) because it's MBR rather than GPT.  I know I can 
convert to GPT without losing data using Partition Wizard, but PW tells 
me that if I do this, it won't be bootable.  How do I make it bootable 
afterwards?

T