Aspire z3771 wont stART? - Acer Aspire Z3771-UR20P - P G630 2.7 GHz - 21.5 TFT DO.SL2AA.001 -

can be a dead CMOS battery or some Power supply issue.
the best thing is to contact the official Acer support service.

If you have a Windows 7 system, log into safe mode by pressing F8 when your computer is booting up. Select "safe mode with command prompt" and press enter. Wait until the windows login screen comes up and then a command prompt should appear. Type net user in the command prompt and hit enter. Once you have done this, you should now see a list of all the users associated with the account. Type net user "Your user account name" and then your new password and hit enter. This should reset your password for the following user account.

Try this one :
XYGNK-R3JJH-H6F4F-HBR2W-9TKKR

try reverting to vga mode
http://www.playtool.com/pages/safemode/safemode.html
tap f8 a couple of times after bios shows, then select vga mode in the list
if that works then you can change to a different resolution in display

Allen Bolderoff wants answers to this question hyjackes, 2013 post in 2018? no time stamp, who knows? but you ask because, Acer has no service manuals. remove what cover to reach what? what is bad? the battery ? Acer Aspire Z3771-UR30P
do mean the ALL-in- ONE PC? that? with missing full partnumber as in the example above?>]\ yes then here is your support page. https://www.acer.com/ac/en/US/content/support-product/3993?b=1
the manual has only one line with remove in it. and is useless. so off to youtube we go. or google all week (not me) 1st ****** hit. https://www.youtube.com/watch?v=52qIGI0aVBg
RTM fail. Google, not me. youtube BINGO.

Check device manage if drivers are corrupt

Hi
Download the manual from the link below.

http://support.acer.com/product/default.aspx?modelId=3980

> try to use the recovery disc that came with the computer,and then try to boot from the disc itself

check the timing

Start laptop and click ALT+F10 - you will enter recovery partition (Note: if there is important data, then don't use destructive recovery).
If recovery fails then you will need to replace hard drive.