Can someone help me set up Outlook 2007?

I am running Windows 7 on my computer. I have been using Windows Live Mail for my email program but it doesn't clear the emails out of my ISP inbox so I constantly have to log into webmail to empty my inbox as it only holds 19mb. I have just tried to configure Outlook 2007 so that I can use that. I have two email accounts. I set the first one up and it downloaded my emails but it keeps asking me for my email address and password and then says it is not correct when I enter it (even though it has already downloaded the mail). The second account keeps asking the same thing but it hasn't downloaded the emails. How can I fix this problem please?