Dell Inspiron 15 (N5040, Mid 2011) - Manual (Page 21)

Memory 21
4 Replace the keyboard (see "Replacing the Keyboard" on page 17).
5 Replace the battery (see "Replacing the Battery" on page 14), or connect
the AC adapter to your computer and an electrical outlet.
CAUTION: Before turning on the computer, replace all screws and ensure that no
stray screws remain inside the computer. Failure to do so may result in damage to
the computer.
6 Turn on the computer.
As the computer boots, it detects the memory module(s) and automatically
updates the system configuration information.
To confirm the amount of memory installed in the computer:
Click Start → Control Panel→ System and Security→ System.
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