The POP3 (and SMTP) settings, required by your email provider, are specific to that provider. They should be on the support pages of whoever who get your email service from. If you're with one of the main UK ISPs, you can find them here:
http://www.kitz.co.uk/isp/dns.htm
Alternatively, open your email client (Outlook, Outlook Express, Windows Live Mail, Thunderbird, etc) on your 'good' computer. The exact location of the information you require will depend upon which program you're using but these instructions (for Outlook Express) will guide you towards where you need to be:
Go to Tools > Accounts and click the 'Mail' tab.
If you've only got one email account it will probably already be highlighted. (If not, click on the relevant account to highlight it)
Click 'Properties' and then the 'Servers' tab.
You'll find the POP3 and SMTP servers for your email account listed there.
Chris