Whenever I print my document, it doesn't exist the document I want to print but many strange symbols appear on the printed paper, how can I solve this problem?

Cold reset
A cold reset changes most system parameters in NVRAM to the factory defaults. However, unlike NVRAM inititialization, a cold reset does not reset the page count, the paper tray sizes, language, or formatter number.
Note If an HP Jetdirect card is installed, remove it before performing a cold reset. Otherwise, the procedure will also reset all the HP Jetdirect settings as well as the printer settings.
To perform a cold reset
1 Turn the printer off.
2 Press and hold down the GO button.
3 Turn the printer on, and continue to hold the GO button for at least 5 seconds, but not longer than 15 seconds. During this process, the Attention LED will turn on.
4 Release the GO button.
Note If both the Attention and the Ready LEDs turn on before you release the GO button, you must start the procedure again with step 1.
5 The printer's LEDs will begin cycling. The cold-reset process will
run until completion, and the printer will return to the ready state.

If not work, tris this

NVRAM initialization

CAUTION Only perform the following procedure if absolutely necessary.
Performing an NVRAM initialization resets some parameters that cannot be restored later.
NVRAM initialization sets all default variables stored in NVRAM back to factory default values or to a default ROM value, depending on the variable. It also performs a system reset.

NVRAM initialization resets the following:

• all menu settings to factory default values

• factory settings such as formatter number, page counts, and factory paper settings