My keypad is not working, when i type in nothing shows i use a Compaq CQ58

In the top bar or you can download complete as a pdf :)

http://www.manualslib.com/manual/491999/Hp-Cq58-200.html#manual

Call Compaq at 800-888-0220
they will mail you one for a small nominal fee.

ccfl screen
all this old are dead or bad. or turn yellow. all do.
all did.
all you can do is turn up the brightness or replace the tubes
CCFL are back lamp tubes. for the SCREEN
CQ58-nnn what, what it the full service tag Partnumber.
ill toss the 50 sided coin and land on cq58-100
the 100 model, is LED and not CCFL lamps
so what OS is running? Windows 7?
i yes, see the users guide on bightness.
read page 26
the magic F3 key.
if the key fails, that means, the drivers loaded on this pc are wrong.
http://h10032.www1.hp.com/ctg/Manual/c03308662

correct drivers are alway here at REAL HP (we are not hp)
im picking w7-64bit now, if not 64bit go back and change that first.

https://support.hp.com/us-en/drivers/selfservice/compaq-presario-cq58-100-notebook-pc-series/5259203

take out the memory and wait awhile then put back in then see what happen if it work you might want to get new memory chips!!!

Some monitors, have an options in the driver section, for others, NVIDIA drivers, have options for contrast of brighness.
others laptops have a key convinations, like FN + another key to bright or contrast the color. look your keyboard for those keys,
sometimes has a little sun design

Remove the screen surround you will see it at the bottom of the screen

On a jammed switch for the batt on the (old) compaq I would take in for repair so is not you the done that damages anything around the battery casing.

look at mfg website for updated driver for WINDOWS 8 for the brand of cd you have

HDMI? Try HP support here: http://h10025.www1.hp.com/ewfrf/wc/product?product=5273500&lc=en&cc=us&dlc=en&task=&lang=en&cc=us