Switching motherboard need help

[NorCalOvrDose]

I have a Hp and my friend has a dell. He doesn't need it anymore and his computer is better. So i took his motherboard and cpu. and put it into mines. now the pc only boots with this _ . Please help me.

 

[raybay]

One likely cause is Windows. If Windows detects any significant changes in the hardware, other than memory, it will refuse to work in a new environment. Could also be the power supply. Some Dells are very persnickity as to what power supplies are acceptable. In some models, the power supplies are proprietary.
We will need to know the models and cofiguration of both systems in order to be of any help.