I install backtrack on my computer,the motherboard of which is GA-MA785GT-UD3H with ATI HD Radeon 4200 origionally installed. The problem is that backtrack can't find the vedio card.
When i type pyrit list_cores it shows

The following cores seem available...
#1: 'CPU-Core (SSE2)'
#2: 'CPU-Core (SSE2)'
#3: 'CPU-Core (SSE2)'

and when i install the driver downloaded from the official website,the driver say also that it cannot find the card.

So can anyone help me????