Will Ubuntu work out on my mother's computer?
Solution 1:
Yes, Ubuntu is certainly the way to go. And not just because your in a situation. I believe it would probably be better in a number of ways.
All the hardware except the mouse should work perfectly, even the printer and scanner.
Ubuntu should work fine on 512MB of ram, the processor is sufficient too. But not for VirtualBox, that needs a much more powerful machine. But it doesn't look like you need it anyway.
4 & 5 - Card games is something there are a lot of in the Software Center. Especially poker, solitaire and bridge. The windows game will probably work, but it'd be best to try the native games first.
Yes, large font themes are available by default. Check the System > Preferences > Appearance program to set the computer to high visibility and increasing font sizes.
There is a way, but get a usb mouse as soon as possible. serial mice are a almost impossible to get working without serious work.
Install the package
ubuntu-netbook-launcher
this is a UI which displays nice large icons on the desktop which my mum really likes. You may have to make a start up item so it launches on login and you should pre-fill the favourites with useful things like firefox.Set your mum up on gtalk with empathy and make sure you two are friends. That way she can ask you for help, but more importantly she can share her desktop with you and you can fix issues even if the any ssh/router configuration gets toasted.
Solution 2:
As most is said by Martin Owens there's only my bit on VirtualBox:
On a 512 MB machine with single core(?) CPU I would not even want to try out Windows in a Virtual Box. Maybe it can be started, but don't expect anything, especially not Windows to run with acceptable speed. In addition you would also need to buy a Windows license for the virtual machine.
For a launcher-like experience as mentioned by Martin Owens also have a look at Docky.