There is not much you can upgrade on that model of Dell, without cost.
I do not have one in front of me, but as I recall, this is a Budget Home computer without a Video graphics card. It has an onboard (integrated) video graphics port, but does have PCI-express slots.
It has a maximum of 800 front side bus.
This means you could add a PCI-Express 1x Video card, provided it would match the level of output of the power supply.
The computer was sold in both Celeron and Pentium 4 models, and was sold with either 256 mb or 512 mb memory. It has a capacity for 2 GB of memory. This indicates you could add a mid to lower level PCI-Express video graphics card and be happier... if you maxed out the memory with two 1 GB modules of DDR2 PC4200.
I do not know what power supply you have, but you would likely need to use a power supply calculator to determine whether a given video card would work with that power supply, once you have the information off the power supply label.
Cost to upgrade memory and video graphics: $150 to $200.
When you are done, you will still not have a great gaming machine, but you will have improved what you have by a great deal, and gaming would be a lot more fun.
