how to use vista with xp pre-installed?

[neuesnotebook]

Hi,

i just bought a dell vostro 1510 with vista business and xp pre-installed because i was told it's faster. i realize now that i don't know how to use this double os. my old laptop was a fujitsu siemens with xp from 2004.

i don't have the new notebooks yet, it was delivered to a friend who says "it's working fine" - but in vista or xp?

my questions: how do I know in which os i am? can i switch between the two? can i transfer software, files and outlook express 6 folders from my old computer without problem (copy-paste via external hd)?

any quick help appreciated, coz i have to go on business trip 1 day after i get the new laptop and it must be ready to use in just 1 day.

thanks!