xp home freezes durning boot up

my friends pc won’t boot, it has xp home, it is a hp. so i installed xp pro corp. version. but i didn’t overwrite the original version, i choose the new folder and named it windows2, i didn’t want to chance losing any info. i reloaded all the apps in the windows2 folder so she could open all her files and get the info. the problem is she can not retrieve her saved e-mails with the new folder set up. how can she do that?, if at all? or can i safely overwrite the original windows files? thank youin advance!! john