i have an hp mini and an hp external disc drive but, when i put disc one in, the disc drive says that its empty, however, the disc drive will read the dlc disc and allow it to install, i have windows 7 home.

AFAIK, that system is way below minimum, and after you get the drive and disk talking to each other, the game cannot run anyway.

What are the Fallout 3 (PC) system requirements?

Minimum System Requirements:

* Windows XP/Vista
* 1GB System RAM (XP)/ 2GB System RAM (Vista)
* 2.4 Ghz Intel Pentium 4 or equivalent processor
* Direct X 9.0c compliant video card with 256MB RAM
(NVIDIA 6800 "GS" or better/ ATI X850 or better)
{Added my note here, the X800 Pro & up also, and
avoid the Geforce 6800 SE, and 6800 XT}
* 4.6 GBs of free hard drive space

Recommended System Requirements:

* Windows XP/Vista
* Intel Core 2 Duo processor (or the equivalent AMD Phenom)
* 2 GB System RAM
* Direct X 9.0c compliant video card with 512MB RAM
(NVIDIA 8800 series, ATI 3800 series)
* 4.6 GBs of free hard drive space

thank you, but the only problem i saw by comparing what i had to what i need on the website it was just a better video card, is there a way i can update or place in a better one? also, it works on my mother's desktop which also has windows 7 home.

The operating system is hardware, and isn't the make / break for inexpensive, low quality machines. Adding real graphics also requires adding a real power supply, good cooling, and probably replacing your current tiny size case with a more generously sized one. You need to ask HP about that sort of thing, but factually, you already failed to exert due diligence when choosing that system instead of something more appropriate for the uses you expected to get from it.

The failure to read the disk is an independent failure separate from the eventual failure to be able to display the game's graphics. I don't think that the PC justifies sinking any more investment into it. If you bought it because it was cheap, you would have been better off buying a normal, but used, desktop system.