Outlook can't find POP or SMTP servers

An odd thing - my windows computer - a Dell Vostro running Windows 7 and Office 2010 - suddenly refused to connect to my ISP (both POP and SMTP), whilst my Mac, iPad and blackberry were all accessing the same ISP (and the same email account) with no problems.

Outlook also refuses to access another account with the same ISP or to set up new accounts, but internet explorer on the same computer is happily accessing the web.

This afternoon I fired up my Dell netbook which runs Ubuntu for the first time in over a year and it too was OK with both email and internet.

Has anyone else had similar experiences with Outlook recently? Have there been any glitches with Windows or office updates within the last couple of weeks?

Or is the Vostro being spiteful because I bought a Mac?