|Sounds like your trying to automate an installer, first try and find out if the particular installer supports a "quiet" installation via command line switches, not many do but considering the other options it's worth finding out.|
Failing that there aren't too many options, the only way I can see would be some sort of simulated button press/click. By it's nature this process is prone to error, especially from unanticipated dialogue boxes and user interaction of the keyboar and/or mouse. If you need to do this in batch the only way is using a third party utility like nircmd.
If you decide to use nircmd I recommend using "win setfocus" and "win dlgclick", it can take some trial and error to work out the buttons ids for dlgclick, but gives a more consistent result with less chance for error than sendkeys.
Batch Variable how to