If it were me, I'd use another computer and select the "Download for another computer" option to get the ISO.
I'd then install it, and skip the CD key step.
Id then call microsoft and say I use assistive technologies and I'm having trouble activating.
Be careful with this, if it's 8.1 with Bing it doesn't have a key. At all. So it needs to have the upgrade done first otherwise it won't activate.
Source: fallen victim to this myself
Wont activate ONLINE.
Phone calls still work :)