For a silent uninstall you can add the SILENT parameter to the aaRemove.exe uninstall program. For example:
aaRemove "PL/SQL Developer [80687277]" SILENT
The [number] depends on your installation and can be obtained from the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
On a 64 Bit OS:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall