I installed MySQL 5.1 on my Windows 7 installartion. I didn't use the windows service option as i wanted to run my server from command prompt.
Now when i tried to start the server using mysqld it did nothing. So i used mysqld -help option to figure out what's going on and it turns out Windows 7 UAC was at it again. So now i have to run the command prompt as administrator in order to ensure that the database works :)