this computer has onboard graphics (ASUS M4A78LT-M-LE) and i've just installed a pciexpress graphics card - radeon HD5450.
the new card works fine but the onboard graphics now doesn't work, it worked fine before - i should have thought i could run the two simultaneously?
do i have to change a BIOS setting or something to get them both working?
previously in another computer, i've had 2 pci graphics cards installed and both worked together just fine (both with twin heads and thus 4 monitors, although i only used 3), so i'm a bit confused as to why the onboard graphics seems to not work now, the reason i got the card was so i could use three monitors, i was using 2 before both onboard graphics outputs.
... to answer my own question ... after a fair bit of research it seems you can't use on-board graphics and a pci-express card at the same time, however you can use either with regular pci graphics cards. (i think there could be the odd exception with specialist motherboards)