Diagnose and fix problems with computers arriving for repair. You can substitute crappy parts for quality ones if you like.
Ensure that broken parts are repaired and assembled in the computer. After that, you can list it for sale and negotiate with customers. Make them believe you're a fool.
With the money you earn, you can develop viruses and infect computers. Become a part of the robot wars and build a robot of your own.
Hack into customers' computers and steal their bank information. Make sure you don't leave a trace behind when you steal the money.
You can explore extremely dangerous areas and research mysterious websites.