How experienced are you with Windows XP and 7, Office 2003, 2007 & 2010, general troubleshooting, Active Directory, using things like Teamviewer, diagnosing networking issues, etc?
You don't have to be good at all these things, but decent experience with Windows and Office are going to be essential to getting past an interview & I'd say if any of the above is something you're not confident with (except maybe Active Directory, which a lot of first line guys probably don't have knowledge of until they start the job) then dive in and try to get some experience on your home PC and by fixing friends PCs before you start applying for jobs.