Can I use an onboard and pci vga simultaneously?

I have an old machine I'd like to get running with dual monitors. The pci vga only has only 1 output port. However, I have another output via the onboard video card. Can I leverage both video cards to go dual-monitor? How would I set this up?

EDIT: Appears that this is possible but, given the myriad possible combination of mobos and cards, I'll just need to try it.

There is no one answer fits all. I have had motherboards with the same chipset and integrated graphics, but on one it allowed and the other it did not.

Without knowing your motherboard, it is not possible to know - however ask the manufacturer or just try it.

In any case, you will most likely need to set it in the BIOS, you may be able to go in there now and see if there is a "both" option under graphics. Again, there is no one answer fits all and it is different everywhere.

My experience has been that not all machines allow two display adapters connected, but assuming the machine boots with both installed and Windows detects both, you're good to go.