All-In-One desktop computer disassembly isn't usually posted.
Technology is still new enough, and required skills needed, dissuade the imparting of this information.
Plus eMachines is about worthless for support info anyway, lol!
A) Construction, and design of the machine dictate a laptop type of environment.
All the hardware components are crammed into one tiny box, with very little cooling inside, and the monitor is attached. (LCD screen)
Free Service Manual,http://www.manualslib.com/manual/232919/Acer-Ez1601-01.html#manual
Just go to the top, and click on the page number you want, or go page by page;
Scroll to the bottom right below the first page, and click on the Green -
Download Manual (154 pages, 9.48Mb)
Going inside the all-in-one means you had better wear an ESD wrist strap, and have the alligator clip attached to a good ground source.
(Electro Static Discharge)
Your body carries Static electricity. Static WILL fry out (Short Circuit), the delicate hardware components inside a computer.
Wear an ESD wrist strap, or prepare to use your all-in-one for an expensive doorstop, if you don't.
Cost averages from $3 to $6. One example,http://www.radioshack.com/product/index.jsp?productId=2103245
[ I connect to an unpainted surface, of the metal frame if an open, empty desktop computer case.
You can also set a large metal serving tray, (Unpainted), on the table you're working on, and connect to it.
Or a large metal knickknack. (Unpainted) ]
Use a multi-compartment container for the various screws you will remove.
Label each compartment for the area the screw/s come out of.
For additional questions please post in a Comment.