You should publish your "little book" as a PDF or ePub file somewhere, with screen shots and photos of course. Millions of people are in need of such a thing.
Organising its publication on line ( as an ebook / PDF ) and in hard ( paper) copy ( and DVD ) has been progressing for a little over a year now ..( and it's not the only "subject" that I'm working on guides for ) ..it ( the PC and also a Mac "Howto" )will be one of the first in a series of guides ) ..I always thought that the "Dummies" series presupposed a level of knowledge and competence in many of the subjects that they treated that was more advanced than many of it's intended audience had ..
It's in 3 languages now ..and translation to two more is in progress ..launch will be in 5 languages simultaneously ..and it will be dirt cheap ( so that the pirates don't bother torrenting it even if they take the time to crack the protection that locks it to a mac address on the downloadable version) ..plus I'd like it to be the kind of thing that grandchildren could easily afford ( say under $10.oo or maybe even under $5.oo ) to buy for their grandparents to help them keep in touch ..Similar thing would be nice for smart phones ..but they change real fast and the market is more fragmented even in Anglophone markets alone.
I decided there was a demand for it ( and similar on other diverse subjects ) after watching my wife ( who is very far from dumb ..but like many a bit technophobe when faced with a computor )..and especially as her work is based around the care of geriatric patients many with Alzheimers /Dementia ( some just have slight memory problems though ..no worse than your average 25 to 30 year old ) in their own homes.
She's frequently asked me to advise her old folks on what PC to buy in order to stay in touch with family that are maybe 500 mile away or more ..they maybe only fire up once a week to real email or to use messenger ( spit! ) or equivalent in Linux ..and sometimes the family buy a laptop for grandma or grandpa ..who are then totally lost with it ( forget how to switch it on ) as soon as the kids have gone home after the weekend ..hence I get lots of volunteer call outs ;-)
I have been printing out and plasticising "How to switch it on etc" "cheat sheets" in French for a while now for many old folks ..and began expanding the idea and going multi format over a year ago..I had bought the "Dummies" guides for some of them ..they couldn't understand it ..it was already too technical.
Linux boxes ( safer as they the old folks ..and in fact many average "users" have a tendency to click any and everywhere ) I get by collecting old machines from our local "town dump" where they are set aside as the arrive ..I cannibalise hardware to make 1 from 3 etc ..and then install Linux ( usually mint ) and give them a "cheat sheet" and some tuition ..and run the occasional group so the better ones can help the others ..
( anyone can refurbish machines like this ..."hint" ;-)
Hardest thing about getting the guide(s) together is the purchase of various domain names ..the trademarking and so on ..and the registering ( France has odd laws for paper "publishers ) as both online and off line publisher in various jurisdictions..and off course the screenshots and animation ( usually "camtasia" or "wink" ) and recording of material , proofreading etc etc ..
( personally I think there's an even bigger market for downloadable 36 hour days and roundtooits than for "guides" ;-)
But if you can make money and provide a real service ..Its worth the effort ..or so I tell myself when my eyes loose focus in front of the screen at 04.00 am or my wife wakes me up at 06.00 am from where I fell asleep in the chair in front of a keyboard.
Btw ..yes I'm aware that proofreading isn't my strongest point ;-) ..I have my prose "triple checked" by others .when I'm not posting or sending emails :-)