I tried to upgrade my XPS 8300 by replacing a MSI GT730 graphics card with a MSI GTX 1050 ti Gaming graphics card.

However, after installing the new graphics card the system won't post and the power button is blinking in the colour amber. There is no beeping sound. Drives and fans seem to start up fine. 

Removing the 1050 ti and reinstalling the GT730 doesn't help... it still won't boot! 

It almost looks as if installing the 1050 ti permanently damaged my motherboard (!!??)

Any suggestions?