i have a hewlett packard deskjet 660c and the problem is when i print in colour it doesnt have any colours coming out so its probably an empty cartrige but it makes a noise that sounds like a cog slipping, but when you only print black it works fine, so if i bought a colour cartrige will it stop the clicking noise

Have you checked your manual for trouble symptoms? Normally, in the back of the user manuals, there's a section for troubleshooting problems.

The clicking sounds to me more like something mechanical - like a loose cartridge, something that isn't seated into place properly . . . but whatever it is, you should be able to check the ink tanks and their placement, simply by opening up the printer, and comparing the color tanks(s) to the black ink tank.

Hey Intel, AMD rulez!

fist thing to try is get a can of air and blow out the printer, you'd be surprised how often just cleaning out the dust makes a difference.

Your hp is probably getting close to 2 years old, or more. That sound is indeed a "cog" slipping.
If you notice inside to the left, there is a small tension arm and gear that the drive belt goes around. Over time this belt becomes worn and stretches so the tension arm cant pull it hard enough to remain in contact. Unfortunatly, it will cost as much if not more to get it repaired versus getting a new printer. Save your money on the color cartridge (they cost about half as much as a printer!)and buy a new printer.

good luck