How do I find the Yahoo Accounts that I have used on my Windows Vista computer?

I forgot some of my yahoo accoounts on my Windows Vistnt names but I know that I used a computer how can I get them I know I go to my computer, c; , program files , yahoo but then what do I do .On Windows XP i would go to my computer,c: program files, yahoo,messenger, profiles, aand it would give me the profiles that I have used on the computer.How would I do it on WIndows Viista though?