This issue appears only if you have installed DAEMON Tools Pro on Windows Vista system and then upgraded your Vista to Windows 7.
How it looks:
- DTPro prompts for activation every start, your e-mail address is already entered and you just click Activate and DTPro seems to be activated, but next time you will get the same activation dialog;
- DTPro Agent crashes;
- DTPro cannot add virtual adapter.

What to do:
Press Win+R on your keyboard (standard Run... dialog will be opened), then enter "C:\Users\All Users" to this dialog and press Enter key. Windows Explorer window will be opened in the specified folder. Find "DAEMON Tools Pro" folder and remove it with all its content. Start and reactivate DAEMON Tools Pro.