What kind of computer background do you have now? What interests you most about computers/computer security?
My suggestion would be to work on a few of the entry-level, general concept certifications first so you can get an entry position into the field. You obviously can't jump to the top right away, everyone has to start somewhere.
My suggestion would be to look into the following certifications:CompTIA A+ : IT TechnicianCompTIA Network+CompTIA Security+Microsoft Desktop Support Technician
The nice thing about the MCDST is that you can also get free training
through Microsofts online eLearning.
Why do I suggest these courses? Well, for starters, the CompTIA certifications will provide you with an excellent foundation to walk into just about any entry-level support position. This is what you'll probably want to look for being a career-changer (something along the lines of 'desktop support', 'helpdesk technician' etc.). I don't think you'll have too much of a problem finding something with a similar salary to where you're at now. The reason I mention the MCDST is because Windows is everywhere and if that's what you're going to support, you should probably know it well.
Once you're in, and get some experience, you may find that something else interests you... and any of the above will certainly help you grasp more advanced concepts no matter which route you choose.
Hopefully that helps answer your questions. And you'll surely get more responses. Welcome to the community