IPhone updating error - Freezing in update.

Hi all.

I have a persistant and irritating issue that whenever I attempt to download and install an iphone OS update, it will get to about 75% completed and then freeze. In order for me to sort this out, I have to unplug the iphone from my computer and install the update on another. This also happens with my Ipad.

Its a pain as it then means I have to recreate my iphone from the last backup.. Not really a problem as I will always have an upto date one, but its just irritating.

Has anyone else encountered this, and solved the problem without having to resort to using another computer or some other method. Would a complete uninstall and reinstall of Itunes help?

Id like to be able to plug it in, install and go without the faf im currently having.

My set up is:
Iphone 4 - 32GB
Ipad - 64GB
Macbook Pro 13inch - 4mb RAM, 320GB hardrive

My macbook is brand new and I was hoping it would have solved the problem by having a new machine, but (maybe stupidly) I resorted this new Macbook from the Time Machine backup of my old one so that all my data was transferred, so I think that if its something to do with the Macbook, the problem has been transferred over.

Any ideas?