I have a pc with 2 graphics cards. When I start the machine everything is ok. But if for some reason I have to restart the computer it dies on me and I can not get the machine started until I remove the second graphics card. Now if I shutdown the computer and then start it all is well.
This is very puzzling and I would appreciate anything you can suggest.

Thanks

IRQ and/or I/O conflict on one or both cards. Like as not it'll boot just as well if you remove the other graphics adapter.

Does it actually support dual GPUs?
Does it have enough power?

Check your BIOS and see if the cold boot options are the same as the restart options if they are not, make it so.

it may not help, but it won't hurt.