GTX 750ti and p7-1235 problem

I recently purchased an eVGA GTX 750Ti to install into this PC. The choice of card was primarily for the low power draw, the PC only has a 300w PSU.

Once the video card is installed (after uninstalling the onboard video drivers), the computer seems to start normally up through 'Starting Windows'. The video hangs here, and I've not been able to fix it so far. Audibly, you can hear the computer get past this point - it starts up, I can type my password and login, was even able to use Ease of Access to navigate a little by ear.

Trying to start in low resolution mode results in the same problem. Any ideas on how to see this fixed?

Specifications
Model: HP p7-1235
CPU: AMD A8-5500 APU (integrated Radeon 7560D)
Motherboard: MSI ms-7778 (jasmine)
OS: Windows 7 64-bit