If you can get proficient with using things like email perhaps Outlook and Windows... Can use Google to stay for stuff especially on the tools/apps/software you want to learn is a huge start. Also checking out Goodwill sometimes you can find books on certainly applications like MS Word or Excel or MS Office etc. Start using that computer. Learn how to browse the web and use the toolbars. Learn how to type is going to really help if you aren't proficient at it. There are many free ones online. Don't be turned off on using the kids typing games or apps. Just get to typing. Use MS Word or Outlook and learn to send emails, hope to change fonts and hope to highlight bold and italicize things. Learn to cut and paste. Etc.
Typing Test You can try that but I've not had a change to try it. I'm on my phone... Lol
Another option that might help is a temp agency. I don't know where you live but I'm the USA we have some tell agencies that have computers with learning programs and tools to help learn applications and such. I haven't been to one in years though. The one I used to use was called Adecco. They would help place you in a job for work... Usually temp or mp to hire jobs and they'll let you come in and learn applications. I didn't really have to use their resources. I self taught myself. You can do it too. Just submerge yourself in MS Windows, Google chrome, Ms office and it should help immensely.
Good luck!
Yeah I saw one for $500 and thought that was a bit crazy. I found it here Acroname - USB Switch for $500.
Not sure if the second one will do the job.