[Solved] led and transistor

[ViSioNXx]

I have an old matrix controller I added some led's to. I am having the problem where they do not cut all the way off. I was told a transistor would solve this. I have 2N3904 but I can not find a certain way to hook it up. Please help?
I think the collector goes to - on led. the emittor goes to ground on board and the Base goes to the tp7 on face of pcb. Is this correct?

Solved thanks to Whitetop.