Custom build PC shows 'No signal' on monitor

[MaxS]

I'm trying to help my friend with a problem he is having with his PC that I built for him about 2 months ago and it has been working fine until today. He installed a PWM splitter today and after installing it, his monitor that is connected with HDMI showed 'No signal' but the computer sounds like it is starting up (HDD light and sound, fans spinning etc). So he uninstalled the splitter and still has the 'No signal' problem and he has tried all the various fixes, checking the fans are plugged into the Mobo slots correctly, trying to boot with just one stick of RAM, tried with a different HDMI cable, trying the monitor on a laptop (it worked) and none of these have fixed the problem. Has he fried his motherboard/PSU?

His specs are:
i5-4670k
GTX750Ti
8GB RAM
Windows 7 professional 64-bit

 

[NiCoM]

Make a list, then check if ANY of the cables in his pc are loose, he probably managed to pull something out or shorten a component while he was putting that PWM splitter in.

Try using the onboard gpu that you have in the i5, simply connect the monitor to the motherboard, if that works then check the cables to the gpu are connected properly, if they are then the gpu is probably the problem. If everything is connected properly in the pc and still not showing anything, then try clearing CMOS and see if that fixes it.

If not then he probably shortened a component (probably gpu or motherboard)