Re: upgrade help
In other words, general use. Most of the time you'd just need to double the RAM for those types of computers, if you're in need of a performance boost.
Other than that, you don't really need to upgrade anything else. That is unless you want to play more recent games. Which will include upgrading to a discrete graphic card, along with a power supply.
In terms of casing, it looks like everything will switch over nicely. I'm just concerned about the front panel connectors for the power button, power & HDD LED, reset switch, etc...because retail companies like Gateway, usually have a proprietary design. And also the card reader.