First check that all your cards (pci and agp) are well inserted, then check that your memory is also well placed.
If you remove the pinnacle card the problem stops?
Try removing all your cards and leaving only the vga card and your new pinnacle card, if you pc works then start adding the rest of your cards one by one (every time you add a card you must let the system load completely and then shut down for the next one so you can be sure there are no conflicts).
Also depending on wich pci slot you put your cards the pc behaves diferent because of the IRQ so pay attention to this too (the best experience I´ve had was putting the audio card in the first pci slot wich is inmediately next to the AGP slot and then all the others, also if you have a SCSI card or an ATA controller it´s recomended that this type of cards be placed on the last pci slot wich is the farest slot from the AGP slot.
If you still have problems please post more specific information about your system.
Good luck