New GPU installed but fan doesn't spin & there is no display

[_leoo]

System Model: Studio XPS 8100
BIOS: Default System BIOS
Processor: Intel(R) Core(TM) i5 CPU 650 @ 3.20GHz (4 CPUs), ~3.2GHz
Memory: 8192MB RAM
Available OS Memory: 8120MB RAM
Page File: 10093MB used, 6143MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
PSU: 350 W

I replaced my gpu with Radeon HD 7790, got it put in.. But when I turn on the computer, there's no display and the fan isn't spinning. What could be the problem?

 

[lostmenoggin]

Did you plug in the power cable?

 

[Martell1977]

Did you connect the power cable to the GPU? If so, you may need a better PSU.

 

[potpolima]

350 W is not enough and probably has no 6-pin pcie connector...get at least 450W with pcie-e 6 pin..