My computer monitor won't turn on?

I have a HANNS-G HW173A monitor I bought it secondhand and I can't get it to turn on I have checked the power cable and there is nothing wrong with it as I have tried it on another monitor and the cable works fine so its not that and nothing wrong with VGA cable either. The monitor didn't cost a lot of money but previous owner did say it worked fine as he tested before he sent it but said he used a different power cable to the one he sent with it. Any ideas of what I should do