Thanks. What I am really trying to understand is is it possible for my to validate my private key using Electrum on an offline PC but without creating a new wallet or sweeping it? What I've noticed is that if I enter the private key in that window the Next button becomes ungreyed. However if I enter that private key with a single character deviation the Next button remains greyed out. In essence I have an old priavte key that I would like to test is still valid but without moving the funds from it.
It is possible.
Electrum will derive the address using the private key that you've provided. The reason why it becomes greyed after a small deviation is due to the fact that there is a checksum in the last few digits of the private key which checks whether the key is entered correctly. This helps the user to identify if they've mistyped their keys. If you're able to derive the correct address from the private key offline, then it would be valid. You don't have to be online to do so, Electrum doesn't interact with any server to generate an address.