How to do I get my HP Color Laserjet CM1015 printer to print in black and white even when it has run out of...?

if one of your cartridge be empty your printer show alarms

you can fix this problem by inject some water into three hole on top of your color cartridge (i personally used special ink for that but water may work too now your cartridge is full - full of water :-) )

printing with black cartridge only:

in XP go to control panel then printers know right click on your printer choose printer properties> color > check print in gray scale > check black and white cartridge only

in Seven go to devices and printers >right click on your printer>printing preferences>color>color options>check print in gray-scale >check black print cartridge only

With most printers you are required to have ink in both the black and color ink cartridges in order to print in black as they work in conjunction with each other. So you will need to have the both color and black ink cartridges with ink.

Some color is needed when printing in grayscale

when you're going to print a document choose printer properties, choose the color tab, and choose print in grayscale and black and white cartridge only