While I'm not entirely sure what you're trying to do, niether Sins nor Entrenchment are tied to one specific computer. As long as you remember your impulse account and password you can download it again on any computer.

all right thanks guys

for ironclad do i still use the same account details to play online

If I do this "Download and Archive" then transfer this file to my PC (no connected to internet atm) then do "Restore Archive" with this file can I install Entrenchment offline?  Just move house and no net connection for a couple of week (can download at my parents).  Or any other way to install offline..cheers.

sorry don't mean  to sound like a prick but only game I purchase for a long time since I play Eve Online pretty much exclusively and it turns out to try rape me with copy protection when I buy the expansion.

Sorry, when you do Download and Archive you do need to be connected to the internet to install from it. It's not really copy protection, it's just that Impulse needs to be logged in. There is a very basic check on installation to make sure it's going to the right account, which is why it failed since you were offline.

If you need to install it completely offline, go to http://anywhere.impulsedriven.com and download the premade archive from there. It should work fine as an offline installation.

As Impulse is the only supported method of doing incremental updates, doing that would be tricky if you don't have internet access on your own machine. You'd need to use the archive option to transfer your existing old version install to a machine with internet, update it there, then copy the updated install back to your machine.