DaLo is spot on here. As a manger in a corporate environment, I expect anyone looking for a career in IT to spend a fair amount of time playing with tech at home. It shows that you are interested in the subject, however, a corporate environment is no place for someone to be playing.
Environments are protected by change control and desktop images are standardised for a reason. I would not hire someone who could not see their way past downloading and installing a piece of freeware to solve a users problem. (You've invalidated the standardisation, now no-one else can support this user. Chances are this application is not backed up nor encrypted. You've added a new application to the Service Catalogue that the rest of the team will have to support, and chances are you've pissed off the Security Director who is going to get his bum kicked by the auditors.)
I know lots of really good desktop support guys with Network or Server qualifications, all trying to get their big break and make it into SysAdmin teams. They are really good but it's tough to get the Desktop Support label removed.
Certifications are only useful to prove that you are not bluffing when you are trying to get your foot in the door, so despite lots of other respondents saying they do fine without them, remember they already have an IT job.
I'd go for the real value-adding jobs - network admin, SQL DBA, web developer, programmer. Support is unfortunately just seen as a commodity.
Use your medical experience. Follow the charity route. Maybe even a medical charity. Good luck, in the right role, IT can be a really rewarding and fulfilling job.