If you've broken the keyboard just replace it. £14.30 from Amazon.
http://www.amazon.co.uk/DELIVERY-SELLER-Aspire-Laptop-Keyboard/dp/B00779DPMW
Simple enough to do.
http://www.pcadvisor.co.uk/how-to/laptop/3369858/how-replace-your-laptop-keyboard/
or just replace the broken key
http://www.laptopkey.com/Guides.php/Acer/Aspire/5741Z/AC10
Good luck!
ChicksFan
March 2014