With regard to the keyboard, USB keyboards have a USB plug hard wired and may be supplied with an adapter to use with a PS/2 port. However, a PS/2 keyboard won't necessarily function when plugged into a USB port (via an adapter).
In Outlook, have you set up four separate accounts for your four different email addresses? If the addresses are actually "aliases" for one TalkTalk account, you may have to use four separate Usernames to retrieve messages for the alias accounts.
For example, if your main account login is "username" or "username(at)talktalk.com", you may need something like these for the alias accounts:
...if that makes sense.