Windows Server 2008 / MySql 5.1 Reconfig (no replies)

Hi,
I performed a first successful installation of MySql server 5.1 on Windows Server 2008. Then, I uninstalled, removed all directories and data, and tried installing again: since then, everything installs correctly but when I run the Server Instance Config program, it stalls to "Start Service", no matter of the configuration (I tried everything)

I uninstalled again and again, rebooted, made sure the service was removed, but it keeps stalling. Even trying to execute the service manually doesn't help (1067: The Service terminated unexpectedly).

Any suggestions?
Thanks,

andrea