the touchscreen on my officejet pro 8135 is completely unresponsive or frozen, buttons do nothing.

Diagnosis

The unresponsive touchscreen on the HP OfficeJet Pro 8135e is typically caused by a "firmware deadlock." This occurs when the printer's control board sends a command to the display interface that fails to execute, causing the UI thread to hang while the background printing processes may still be active. Because this model utilizes a capacitive touch screen, a buildup of static electricity on the digitizer or a corrupted temporary cache file in the volatile memory can prevent the screen from registering touch inputs. You can confirm this is a software hang rather than a hardware failure by checking the status lights on the printer's chassis. If the power light is solid blue and the printer responds to a "Print Test Page" command sent from a connected PC or mobile device via HP Smart, but the screen remains frozen, the issue is isolated to the display controller. If the screen is completely black or flickering, it may indicate a loose ribbon cable connection internally, but 90% of these cases are resolved through a full power discharge.

How to Fix It

To resolve a frozen touchscreen, you must perform a "Cold Boot" to clear the printer's temporary memory and force a hardware re-initialization of the display panel. Follow these exact steps:

1. While the printer is still powered on and the screen is frozen, disconnect the power cord directly from the back of the printer. Do not simply turn off the power strip.
2. Unplug the other end of the power cord from the wall AC outlet. This ensures there is no residual current flowing into the power supply unit.
3. Wait exactly 60 seconds. This allows the capacitors on the main logic board to fully discharge.
4. While the unit is unplugged, press and hold the physical Power button on the printer for 15 to 20 seconds. This drains any remaining electricity from the internal circuitry, forcing the firmware to reload from the ROM upon the next boot.
5. Plug the power cord back into the wall outlet first, then firmly seat the cord into the back of the printer.
6. Wait for the printer to complete its startup sequence. Do not press any buttons until the home screen fully loads and the "Ready" message appears.

If That Didn't Work

If the hard reset failed to restore touch functionality, try these advanced recovery methods:

• Force a Firmware Update via HP Smart: Since you cannot use the screen, use the HP Smart app on a connected computer. Go to Printer Settings > Advanced Settings (which opens the Embedded Web Server/EWS). Navigate to the "Tools" tab and select "Printer Updates." Check for updates and push the latest firmware to the device. A firmware overwrite often clears the corrupted display driver.
• Clean the Digitizer Edge: Capacitive screens can freeze if dust or ink buildup occurs around the bezel edge, creating a "phantom touch" that locks out other inputs. Use a lint-free microfiber cloth dampened with 70% Isopropyl alcohol. Gently wipe the entire perimeter of the screen where the glass meets the plastic frame to remove conductive debris.
• Disable "HP+" Cloud Services Temporarily: If your 8135e is linked to an HP+ account, a synchronization error with the cloud can occasionally freeze the UI. Disconnect the Ethernet cable or turn off your Wi-Fi router for 5 minutes, then restart the printer. This forces the printer to boot in "Offline Mode," which may bypass the hang.
• Perform a Factory Reset via EWS: Access the printer's IP address through a web browser on your network. Go to the "Settings" tab > "Restore" > "Restore Factory Defaults." This will wipe all network settings but will reset the display controller to its original state.

Heads Up

• Avoid using ammonia-based glass cleaners on the touchscreen; these can strip the oleophobic coating and lead to permanent dead zones or increased sensitivity.
• Always plug the printer directly into a wall outlet rather than a surge protector or UPS if you experience frequent freezes, as some power strips do not provide the consistent voltage required for the 8135e's logic board.
• Keep the printer's firmware updated monthly. HP frequently releases "stability patches" specifically for the OfficeJet Pro series to prevent these UI hangs.
• If the screen remains unresponsive after a factory reset and firmware update, the digitizer ribbon cable may have come loose from the internal connector, which requires a professional hardware repair.