I own a Dell Inspiron 530 with an Intel Core2 Duo CPU E7300 and 4 GB RAM. I recently downloaded Mass Effect from Steam (on sale!) and my nVidia GeForce 6600 LE isn't up to the task of running the game.
What do you recommend for something reasonably priced and easy to install?
Good news: You have a PCI-E slot, which means you can get a decent video card.
Bad news: You have a 300 watt power supply, which will not support many of the newer video cards as they tend to require a lot more power.
You'll probably end up having to purchase a new PSU (Power Supply Unit) and a Video Card together and install them both. Luckily, decent PSU's have come down greatly in price.
EX: For mass effect with your system specs, this might not be a bad idea