Building both parents a pc. Need some Insight

Hey guys Sorry if I screw up the area i'm supposed to put this in.

So here we go, My parents both have an intel i7 first generation computer that run super slow(each one have a pc to their own). Recently they have gotten worse, we have tried many things to make them run better like new hdd's and fresh installs and what not but nothing is working. My dad said they will just have to live with it since they are a little tight with money because they are helping with their parents/step-parents bills. So, with all this cash I have lying around not being used for anything good I have decided to build them both new pc's. I have $900 to spend on them to be exact. Heres the thing, My father is a workaholic. He uses his computer for everything. He works with linux. AIX tcp-ip stuff works for the FBI. My mother works from home on her work pc but is always using her pc for bills pictures shopping and watching netflix, and the way my mom is it needs to be lightning open google chrome before she is done clicking it fast. my dad on the other hand just needs a pc that can run two 27 inch 1920x1080 monitors with one having the desktop and the other having their security cameras. So, I need some help on what to get them...I have 2 ATi 5770's I'm going to give each one and a 1tb hdd for each one.....oh, and the processor needs to be AMD...they dont need an intel $250 and beyond processor....ANY help would be appreciated. If I need to clarify anything let me know and I will do my best. Thanks guys.

This build should fit the bill.

I like it....although...could I use an x6 and get a much better performance?

put a 5770 in each and a 1tb and they will be set

No. The main performance bottleneck affecting the programs your parents are likely to be using is the storage. There is not really a need for a six core CPU unless the user is going to be gaming or rendering. 

Okay so both of those more question...this just occured to me....could the i7's be put into newer hardware and then work just as good? if not better? Im just wondering really.