Hello,
Please reset the mobile ,
Resetting Your Device Soft reset Occasionally, you may need to reset your device. A soft(or normal) reset of your device clears all active program memory and shuts downall active programs. This can be useful when your device is running slower thannormal, or a program is not performing properly. A soft reset is also necessary afterthe installation of some programs. If a soft reset is performed when programs arerunning, unsaved work will be lost. To perform a soft reset 1. Remove theback cover. 2. Use the stylustip to press the RESET button located between the SIM card and the storage card slots. Your device restarts and displays the Home screen. Hard reset You can also perform a hard reset (also known as a fullreset). A hard reset should only be performed if a normal reset does not solve asystem problem. After a hard reset, the device is restored to its defaultsettings-the way it was when you first purchased it and turned it on. Any programs youinstalled, data you entered, and settings you customized on your device will be lost.Only Windows Mobile® software and other pre-installed programs will remain. Warning! Your device will be set back to factory default settings. Make sure thatany additional installed programs and/or user data have beenbacked up before you perform a hard reset. Managing Your Device Important IfEncrypt files when placed on a storage card is enabled, backup all files from the storage card before using Clear Storage, hard reset,or updating the ROM system software. Otherwise you will no longer be able toaccess the encrypted files on the storage card. Use ActiveSync or WindowsMobileDeviceCenter to transfer files between your storage card and computer. After theprocedure, copy your files back to the storage card. To perform a hard reset 1. With thedevice turned off, press and hold the VOLUME UP and VOLUME DOWN buttons, then briefly press the POWER button. 2. Continuepressing the VOLUME UP and VOLUME DOWN buttons until you see this message on the screen: This operation will delete all your personal data, and reset all settings to the manufacturer default settings. Press VolUp to restore manufacturer defaults, or press other keys to cancel. 3. Release theVOLUME UP and VOLUME DOWN buttons. 4. Press theVOLUME UP button to perform the hard reset, or press any other button to cancel the reset.
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I think the only way you can unlock htc desire hd screen in this condition is reflash your mobile phone. Go to nearest local mobile repair shop expecially for htc brand and asking them to reflash your phone. This method should unlock htc pin and password to default factory setting, but if this method still not working looks like you have hardware problem.