>>On Ctrl+Alt+Del combination (calling Windows Security window) you have Change Password... button. Could you use it? - This will change your network passowrd.
>>
>
>I didn't know this trick. Ok, this worked and now my SQL Server is working. Does it mean, I have to use this password everytime now?


No, go to the properties window and change the property
"Start and run SQL Server in the following account"


>
>>
>>>>Why can't you change your pasword?!
>>>
>>>This password is used to log into local network. I installed it at work. Here is what happened: for couple of days I left my computer running, when I go home. On Friday I installed SQL Server. Then at some point I needed to re-boot and the system didn't let me in (my password expired). I asked our Network Administrator to resolve this issue. He set me a new password. But now SQL Server refuses to start. I don't know, how to make it aware of my new Windows (network) password. I just re-booted again looking if there is an option to change password, but it was not.
>>>
>>>Do you know, how can I do it?
>>>
>>>Otherwise I will re-install it.