Bless!
Still I know your pain, my neighbours in their 80s use a PC and I 'support' them. As in every couple of months I rebuild it as hes downloaded a virus/removed an important file, deinstalled/reinstalled the printer/scanner at least a dozen times, messed up teh firewall, updated something that he shouldn't, installed new wireless drivers or god knows what else.
Still, I'm working on training Siobhan to do it. She already worked out how to change the CD in her Hifi system in her bedroom and press play to get the new music
(Shes 19 months old if anyone doesn't know
)
We were playing the teletubbies game on CBeebies the other day as well, using left/right key although she hadn't worked out how to avoid stuff