Email Accounts: Only Receive Email

I have 4 computers, all have Windows XP. I recently replaced the 1st which was my Laptop with a Dell XPS that runs Vista. Since then my email accounts started having problems. I can only receive email on one account. but was able to receive all email accounts one the main Desktop which is wired to the router. Now I have replaced this desktop with a new one it also runs Vista, and now the same thing has happened; I only receive email from one account. I tried deleting all accounts and set them all up again same problem. I have MS Office 2003 which has office outlook and it to does the same thing. I tried deleting accounts on both trying to single out the possibility of conflict, but still no luck.