was working - now dead

While my fast PC is being fixed, i tried opening second life on my old PC:
1.4 Athlon
64MB MX 400 card.

Second life 14 worked.. ok the animation was like a security monitor video, but i could log in and chat.. the resolution was absolutely basic but it worked.

So.. i thought.. ok update the Graphics card.. that might improve things.. so i put in a GEFORCE 7800 GSOC nVIDIA 256MB GDDR3 AGP card.

Now second life 14 wont run.. crashes on start up..

ive tried uninstalling and reinstalling.. no change..

so what happened? why doesnt it run on the better graphics card? especially when it ran on the much reduced capacity of the old card.