A PCI video card MAY work but since a PCI bus is slower than a PCIeX16 it won't give as good results. Whether you have the same intermittent problem depends on where the actual problem is in the PC. If it is strictly in the PCIeX16 I/O bus then a PCI should not have the intermittent problem.
If you replace the motherbpard only another Dell 9150 motherboard will fit and work. However, if it gets to that point you really need to consider whether you want to put additional $$ into an "old technology" PC or if you want to put those $$ toward a new PC with new technology. Same way with installing a PCI Video card. It may just be that the best option is to live with the intermittent problem until you can buy a new PC.
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