I just built this HP Workstation for internet browsing, all eBay - $80 for the chassis, $14 for the ATI video card, $30 for a Win7 disk with COA, and $100 for a 256GB SSD. Came with 4GB RAM and DVD RW. Has 8 USB ports including 2 on the front. Mic and headphones in back or front (both). I drive a nice LG monitor. Set resolution as needed for her sight ...
So the question is are you building it for her? Or are you just buying ...
HP business class computers are good. They generally have good sound systems built in. Can not say the same for Dell... Usually somewhat noisy ...
Does she Skype? Does the monitor need built-in camera and mic? Do you need to drive external speakers?
How much desk space does she have? Can a tower sit next to her desk?
This HP workstation has variable speed fans so as long as there is not much heat (no HDD spinning), it's very quiet. If you get video with large heat sink and no fan, it's even quieter ...
If just buying, I'd look at refurbed HP workstations from Microsoft with SSD instead of rotating media ...
Monitor is your choice. Many folks are now switching to HDMI flat screens ... They work fine
My wife bought her last puter from COSTCO and loves it. She especially likes the Concierge Service for two years. Anytime she has an issue, they fix it pronto over the net and a friendly. They make it much nicer for her.
I don't need that, or want that. But your older lady might ...