So my office is upgrading their desktops and they basically gave me one of the old ones. Can it handle running blender and unity?
Dell Inspiron 530
Core 2 Quad Core - not really sure what that means…
8 GB Ram
500 GB HD
Graphics card: GeForece GTX 650 2GB GDDR5 (this one is mine and have yet to install it)
Power Supply: 750w (I’m pretty sure but I’ll have to double check)
It’s an aging machine (the Core 2 Quad chip is around 6 years old), but it should be good enough to run Blender and Unity (F12 Cycles rendering might be a bit slow though).
The GPU actually should be a pretty decent mid-range model so realtime graphics should be smooth.
You will have a pretty big PSU reserve which might be good thing to have if it’s as old as pc. This PC with new GPU should handle blender normally; can’t say anything about Unity - have no user experience but i think it is less demanding.
In browser called Firefox, if rightclick on selection there is a popup menu line - Search Google ( 
sorry, could not resist). Wiki has a good amount of historical and technical information on NVIDIA GPUs (your existing GeForce 8300 GS, according to Dell specs, included) and Intel/AMD CPUs and amongst waste of specifics gives general overview which is what.
Here you can see Cycles render test results table - hope your CPU is listed there.