How must I operate my C720 notebook to register product as the instr advises?

Acer has the user manual for the C720 on their support page. If you start on the Acer homepage: https://www.acer.com/ac/en/US/content/home . Scroll down to the bottom of the page and select Drivers and Manuals (second line in the second column "Service"). Then use the drop-down menus to select Category = Netbook, Chromebook, Series = Chromebook adn Model = C720 . The C720 product page is currently https://www.acer.com/ac/en/US/content/support-product/4984?b=1 . Expand the Documents section then click on the Download button on the right side of the page on the User Manual line. The direct link to the manual is http://global-download.acer.com/GDFiles/Document/User%20Manual/User%20Manual_Acer_1.0_A_A.pdf?acerid=635538850729499895&Step1=NETBOOK,%20CHROMEBOOK&Step2=CHROMEBOOK&Step3=C720&OS=ALL&LC=en&BC=ACER&SC=PA_6 .

I hope this helps.

Cindy Wells
(The manual is a PDF.)

Google it

I’m happy to help further over the phone at https://www.6ya.com/expert/wynn_5ba0205233ebfc15

let it charge all the way and try it again, if that doesn't work pull the battery and reinsert it aside from that it may be cooked

any printer

https://support.google.com/chromebook/answer/1080595?hl=en

You can find the user manual under documents

http://us.acer.com/ac/en/US/content/drivers/4984;-;C720

What you mean of set up?

You should find the answer you're looking for, here:
http://blog.laptopmag.com/how-to-set-up-google-print-on-your-chromebook

Watt is the exactly trouble ? Bios restore or sistem restore ?
Bios Restore Only disconect the backup batery inside the lap
System try restores system from a hard disk