There is a thin plastic strip at the back of the cartridge carrier called the encoder strip.
It should sit in a sensor on the back of the carrier (you wont be able to see it but you might just feel it)
sometimes the strip pops out of the sensor- so the printer doesnt know where the hell the cartridge carrier is causing it to either just not move or wack about like a rabid dog.
You can try to relocate the strip by "GENTLY" pulling it down, then forwards then up slightly- theoretically relocating it in the sensor.
You may just get lucky but its unlikely, it seems to be a common fault, Hopefully you got it free with your computer, and you didnt really pay good money for it!
if its still in warranty just take it back if the above doesnt work, if its not and the above dosent work, smash it intop tiny peices with a very large hammer and go and buy an epson! you may have seen the price of the lexmark cartridges- they give the printers away free because the cartridges cost more than the printer would in the first place! buy an epson and buy jet tec comp-atible cartridges (keep the free ones they give you sealed just in case you ever have to send it back you can put them in to make it look like you used them all along) the jet tec cartridges have been tested to be as close as you can get to the originals and the print quality is great!