Lexmark X4270......All in one....computer recognized it two days ago, but today it isn't doing anything. Can you help me?

A quick fix for most communication errors can be achieved by resetting the printer and/or rebooting the PC. Simply disconnect the printer from your computer. Reboot your pc. Unplug and re-plug the printer into the power source to reset it. When the printer turns on, reconnect it to your computer. Then try to print again once the computer fully recognizes the USB connection.

If that doesn't help, try the steps below:

1. Disconnect the printer from your computer.

2. Re-brick your printer. Pull out the power supply, black box where the power cord is plugged in at the back of the printer, and put it back after 30 seconds.

2. On your computer, go to Control Panel > Printers and Faxes.

3. Delete the Lexmark print object.

4. Reboot your pc.

5. When your pc turns on, reconnect the printer.

6. Wait until your pc fully recognizes the USB connection. To check, go to Control Panel > Printers and Faxes. If you see a new Lexmark print object in the list, then try to print a document again to verify that the problem is fixed.

You may also try to update your printer driver by visiting the Lexmark website at http://bit.ly/gKXn7F. Select your operating system, download and execute the file.

If the problem continues, please contact Lexmark Technical Support Center for additional assistance.

Try to update your printer driver. Please visit the Lexmark website at http://bit.ly/gKXn7F to download and install the printer driver for your Lexmark X4270. Select your operating system, download and execute the file.

Have you installed the drivers for the AiO? It is a must before being able to use the device. Please follow the link below to install it.
http://www.fixya.com/support/r3559995-installing_devices_on_pcs_and_laptops

Here is the link to download the User's Guide (Lexmark X4250, X4270) from the Lexmark website. Here's the Setup Sheet (Lexmark X4250, X4270) for more information about setting up the printer itself. Hope this helps.

Error 1203 is an issue that occurs either when a cartridge is bad or the printer cartridge Slot is bad...

1 - try cleaning the copper contacts of the both carts and cart slot in the printer and try again..
or
2 - when error shows up, shut the printers power off; wait one minute and turn it back on press copy.
Please come back and just gave a vote, it will gave me some satisfaction to know am helping some one so I will keep on helping.
All The Best: Pineworks

Disable UAC and try to install it again

Go to Control Panel -> Printers. Is the printer listed here? Is the printer Online (It will say Online or Offline next to the printer tile)? If it says Offline, the computer cannot currently see the printer so check to make sure it is plugged in and turned on and that the cable is connected from the computer to the printer. If it is Online, right-click on the printer tile and select Properties. On the General tab, click on the Print Test Page button. After a few moments, the printer should spit out a test page. If this prints out, your printer is working properly. If not, let me know what error messages (if any) it displays or the overall printer behavior (blinking lights, beeps or other noises, etc).

Lexmark Driver download try here

Goto lexmark.com to download drivers, follow instructions for download and install, make notes so you have it in front of you as you install.
Another option is to shut computer and printer off, turn printer on first, then computer, and see if it will recognize the printer automatically, you may have to select your model from a list, you may want to try this first, it would be faster if it works.

Here is the driver for your printer. Pick your OS,download and install.

http://downloads.lexmark.com/static/229-1-0-439.html?ccs=229:1:0:439

Also did you install any software that came with your printer?