External hard drive`

I have a Western Digital External hard drive. I have two pc's connected to the same router. Same email only one is Vista and one is XP Is it possible to store both memory on one hard drive box. This probably sounds stupid, but I got to ask Thank You Doralee

i think OP wants to use same email "profile" from both xp & vista. depends on the email app.
I'd try the email in operausb. http://www.opera-usb.com/
i run the same operausb browser from either xp or vista.
i think another possibility is to use any email app, but use an imap account. (but can do this only if have imap...)

more on opeausb: i also have two different "no-install installations" of operausb. both can run from both xp or vista. can run both operausbs simultaneously. to distinguish each, they have different color "skins". but I don't use the mail, so don't know if that may cause complications.