Uh, you don't "have to have a Windows Mail account" to reply to a job ad -
nobody has one, there's no such thing !! You just give them whatever email
address you do have. It might be through your ISP, i.e. Verizon, Cox,
Comcast, etc., or it could be a MSN-Hotmail-Live, Yahoo, Gmail, or any
number of other email providers - you get them from everywhere for free - I
have one I use for potentially SPAM generating people at mail.com. Put it
on your application and then logon the internet to that site's email and
check it from time-to-time.
If you want to set it up as an account in Windows Mail you can via Tools >
Accounts, but you don't have to and it won't change your (e-mail address removed)
address. It just provides another place to check for mail. If you want to
do that, like t-4-2 said, let us know the part after the @ symbol and we'll
help you through it.
Good luck with that job app . . . . . . .