No a video card will not stop the POST:
This is POST:
1.Test the power supply to ensure that it is turned on and that it releases its reset signal.
2.CPU must exit the reset status mode and thereafter be able to execute instructions.
3.BIOS checksum must be valid, meaning that it must be readable.
4.CMOS checksum must be valid, meaning that it must be readable.
5.CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
6.The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
7.I/O bus / controller must be accessible.
8.I/O bus must be able to write / read from the video subsystem and be able to read all video RAM.