After connecting dvi and HDMI cables nothing shows up on screen just no signal

[StandardJack]

I take my PC to my friends house where I plugged it in and it worked fine, I take it back and nothing works, I connect everything and it's all fine but the monitors say no signal.

Please help
Thank in advance

 

[maxwellmelon]

check everything is pluged in all the way. a power cable or graphics card or other things can come loose when carrying a pc