I can connect to my host with PuTTY. But when the PuTTY terminal asks for my password, I am not able to enter any letters.
I reinstalled putty.exe, but the results are the same.
Can anyone help me please?
If it just doesn't show anything, this is a security feature of Putty. Type in your password normally and press enter, you should get in.
Putty tries to stop people from knowing how long you password is by not showing it at all in the command prompt. This means that you might think you are unable to enter it, while in reality you are.