Problems in disinstallation NAS 4.0

I had NAS 4.0 installed on my computer with the two services installed and on. I have canceled for error the two services with a bad batch , and then I have tried to reinstall NAS 4.0 from cd. It proposes to me to Repair or Remove , but Remove closes with a generic error and Repair stops with “Error 1923 - NAS could not be installed.Verify if you have privileges to install system services”. But I’m Administrator and if I try to install another service (other than navision) , it runs. Is there anyone can suggest me something to do?

I’ve solved working in registries (regedit). I’ve saved every item containing the string “Navision Application Server” , and then deleted them. Then It is possible to re-install from CD. Another interesting thing is that in 4.0, Navision Application Server Manager does not work correctly , that is, in SQL option , It cannot present any choice in parameter Nettype. Therefore NAS says the error “Parameter Nettype Not valid” , and the only way I’ve found is to regedit and modify the corrispondent registry voice.