I have a Dell 1720 LP. I bought 128m memory card, so the printer can print a PDF of longer than 10 pages without locking up. I put in the ram, powered it up and all lights are flashing. The computer won't communicate with the printer. I've already changed the printers memory size on the computer to reflect this newly installed chip/card. Is the memory bad or is there some other trick to make this work? Help appreciated.