Hard Reset HTC Dream

1. Press Power button to switch off device. 
2. Press and hold the Home button + Power button at the same time. 
3. Keep holding buttons untill black screen with warning sign will appear.
4. Next on press ALT + L.
5. Then Alt + W for 'wipe data/factory reset'.
6. Press the Home + Back key.
7. Device will restart and after that u can use it.

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.