Motherboard dead?

Hello, today I was finishing of making my pc and apparently put it on the wall outlet to make a diagnostic and see if it works properly. But it doesn't start... The fans aren't moving (even the PSU one), so I looked the internet and saw I connected the wrong way the USB cables of the case. I plugged them in and... no, it won't start. Any help? (p.s: I hope not to be dead, even if it was free, I mean I took it out because of performance issues and changed it) Thanks in advance! Oh, and I'm not sure if the motherboard is a SiS 98 or SiS 671, because on it write both things. I put the subcategory ASRock because there's no SiS category.