Dell a940 AIO makes noise as soon as i turn it on

Found this: http://support.dell.com/support/edocs/systems/a940/a940en1.pdf

Page iv identifies the location of the scanner lock

Page 44 contains the following

• You unlock the scanner bed. For help locating the scanner lock, see the picture of the printer on page iv.

Page 51 contains

Unlock Scanner message
The scanner is locked. To unlock it:
1 Press Power to turn the printer off.
2 Use both hands to lift the printer (scanner unit) until the scanner support
holds it open.
To the left and beside the scanner support is the scanner lock. For help, see
page iv.
3 Pull the scanner lock toward you to unlock the scanner.
4 Using both hands, lift the printer (scanner unit).
5 Push and hold the scanner support back.
6 Lower the printer (scanner unit) until it is completely closed.
7 Press Power to turn the printer back on.

Hope it helps.