How to reset Sony ericsson p990i if Touch screen not working?

To reset a Sony Ericsson P990i when the touch screen is not working, you can perform a soft reset by removing the battery. Simply turn off the device, take out the battery for about 30 seconds, and then replace it. If that doesn’t help, you can try a hard reset by pressing and holding the "C" key while powering on the device until the Sony Ericsson logo appears. Be aware that a hard reset may erase all data on the device.