Forget it
Theres absolutely no money in repairing PCs, whether its failed hardware, or users screwing up their machines themselves.
The worst thing about that line of work is that if anything, and I mean anything, goes wrong with a computer you've worked on at any point in the future, it must have been your fault. The amount of potential hassle is unreal.
Pc's are just too reliable is another factor, and the general public too unreliable!
I stopped doing that sort of work 4 years ago, and now concentrate on offering services ie IT Consultancy to small business; better paid, less hassle, when it's done, it's done!
You would do better to find some area you can work in that offers a service to business rather than deals with the public at all!
Hope this helps
SC