Your mum DOES NOT need anywhere near an i5. A Sandy Pentium or Celeron will do just fine with a B75 motheboard. Either go all SSD or all HDD, your mother will probably get confused with two disks showing up. It may cost a lot, but I'd just go for a 256GB SSD, and add another to a JBOD is she needs more space.
Intel Celeron G530 ($50)
Sandisk Extreme SSD 240 GB ($160)
Corsair CX500W ($50)
Fractal Design Core 1000 ($50)
Do not get Windows 8, it makes anyone over the age of 8 (aptly named I guess) cry when they first see it. I am an exception, but just don't risk it with anybody. I just love the look on people's faces when I put their OS on an SSD and they see it boot up. Many get confused if you have an SSD for the OS (As it defaults to the C: drive) and a HDD for storage (It usually goes to D: or G:). The OS will start popping up windows saying the primary disk is full (The small SSD) and it makes people terrified. You can show them all you want that there's a 500GB Blue if they'd just click on it, but they'll forget every time. Safest bet is to just load it all onto an SSD, unless you're a very comprehensive computer user (I'm talking registry edits,and other nitty gritty tasks to make sure the SSD and HDD work well together). I'm amazed that the Sandisk Exreme (A pretty good SSD) is that cheap, and so is the 840, but the 840 and 840 pro have a MUCH shorter life cycle and data will deteriorate much quicker. That about sums it up. Also, try throwing something like a TX3 on the CPU to keep it literally freezing (The digital thermometer inside the CPU detects lower than ambient temps) and extremely quiet. That motherboard has HDMI, DVI, and VGA all off the integrated graphics. VGA is the worst, so try not to use it, but it's okay if you have to. HDMI would be really great, but don't let anyone rip you off on the cables, you shouldn't pay more than $7 for a short HDMI cable. I can also make some keyboard and mouse recommendations if you need that my mother and grandmother like (and maybe a monitor or two). My fingers ache, and you're the third person (I think) on OCN that I helped comprehensively today, so I'm spent. 11PM here, got work in the morning. G'night. PM me if you have any questions. I'm about to literally fall asleep over my keyboard. *soft snoring noises*
EDIT: All of these prices are from Amazon(dot)com US website. I think they have an AU site. I know they have a UK one, and they offer free shipping for all of them, undoubtedly. I think there's also something like 'auspcmarket' over there too.
Edited by 267267123 - 12/4/12 at 11:32pm