I don't know what's wrong for you with QMC2, but you can try my front-end, Negatron
In June, I tackled several issues that appeared since MAME v0.186 preventing third-party front-ends from properly managing some emulated consoles and all emulated computers. I had to create my MAME fork to achieve that, called NegaMAME. It's a temporary situation until when somebody at MAME dev will fix this but other priorities are constantly creeping up so I don't expect this to be fixed before several months, maybe a few years.
At first, you may not understand how things work in Negatron. But once, you understand the logic of how to use it, most people just appreciate the ease of use.