b450m steel leged

So my mouse has been having issues for a while now and I'm not sure what to do. Every couple of minutes, the mouse cursor will stop moving for a split second. This gets annoying really quickly and messes me up while gaming or scrolling. The following are some things that I have tried in order...

I bought a brand new b450m steel legend, when I went to build my pc I could not get the motherboard to turn on (only the leds would turn on). I thought I was doing something wrong so I decided to pay for a Technician to build my pc, but same thing happened and he could not get it to turn on...