Do hard reset and every thing will be ok.
For hard reset follow this.
- Turn the power off. If your HTC Desire is frozen, pull the battery out and reinsert it
 - Hold the Volume Down button
 - Press and release the Power button
 - You are now presented with a menu that allows for Fastbook, Recovery, Clear Storage, and Simlock
 - Select Clear Storage by pressing the Volume Down button
 - Press and release the Power button
 - Now simply confirm your decision: Volume Up for YES and Volume Down for NO
 
and also can see this.
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