You will be able to play them yes, but don't expect high settings or resolutions without some lag.
The PSU may need upgrading as well, as I doubt the 300W supply included will have PCI-E connectors (or even if you should use it).
Thinking AMD 7750 which gets power off the pci bus only, low end. If graphics budget is higher I have a 500W+ PS on an older system I can swap out. If I can get 1028x762 until then in this system I will be happy!