Paste the private key under the 'Wallet Details' tab on bitaddress.org.  Make a change or three, then tell it to generate the new address.  If gives you an address, you made valid changes, if it says 'invalid private key', try some other changes instead.  There are just a few things you cant do, like using I, 0, l, 0,o.

I've used armory and the QT client to double check addresses, but it can be hard getting them to run off a live CD.  You could do all of this with a spare drive, then when you are finished, boot off the live CD and overwrite the drive with zeros several times.