Many of you are seeing the benfits of moving your email accounts to a provider such as Google (Gmail) for exceptional services in both functionality and reliablility. Mark my words with the advent of Windows 10 (don't get me started grrr...) things are bound to move to online computing and most of us will not be bothered as to what platform our applications are running on.
The method I'm going to outline here will be using Thunderbird email client which can be download from here.
Open Thunderbird and connect to your existing email address.
Add another account and connect to your Gmail account. You will need to turn IMAP on in the settings to Gmail and also enable "Allow less secure apps." in your Google account settings.
Once you have both loaded wait for all data to synchronise which can take some time depending on the amount of data in the account.