I was in the same position 6 years ago. I had to take early retirement at 35 and wanted to start in IT. I got a first line support job with a major computer manufacturer doing hardware support with just the A+ cert.
From there I moved up the company and added more certs along the way.
The starting positions are desktop support - Get the Microsoft Windows 7 or 8 exams. If you want to go further start on the server certs. Once you have done 3 of 4 Microsoft exams you will be bored to tears with them but you should be in a better position to make a decision on where you want to go. If you choose to go with the Linux route then most of what you learn will be self taught but Cloud and Virtualisation jobs seem to be showing up a lot in job searches. I am VCP - Vmware Certified which my company paid for and if you can find a company that is willing to invest in you the sky's the limit. When negotiating for a wage always take slightly under what they offer if they are willing to pay for some training that way you help build more marketable skills. There are a LOT of specialisations out there but really you would need at least 12 months doing the basics before you decide what you want to go after next. If you decide on cloud technologies you will need SAN technology experience and will need to go after some Linux skils rather than Windows.
To make yourself the most marketable in the 12-18 month of your career a couple of Server 2008/2012 with exchange and SQL of some sort will help you apply for an Administrator role but you would need to be pretty dedicated to learn all that on your own with lots of matchsticks and coffee to keep you awake.
Definitely do ITIL foundations 2011 is the new version its boring but a dawdle to pass.
Do a networking cert CCNA does seem to be the most popular but there are other Networking courses out there that certification pays better. The Network + exam from Comptia is pretty easy and will give you a grounding in the basics.
There is no quick solution in your first couple of years but good luck.