I took the back off my toshiba ,did touch ,put it right back on and it won't start .

[deeh49]

Got a black screen ,so I took off the back and the didn't know there were only 2 screws for the battery .Anyway I put the back right back on ,didn't touch anything . Now it will power on and right off.

 

[C12Friedman]

Something is loose inside or a wire is misrouted (most likely loose). I'll suggest looking at a disassembly guide on YouTube for for your specific model to see what may have become loose