You can run an executable from labview using the system exec function
under the communication palette. This acts like the command prompt in
windows. You will execute your exe just like in the command prompt.
As far as inputs and outputs you can't do this with and executable
that I know of. I do know that you can create a dll in matlab that
will allow inputs and outputs. Once again in LV you can call this dll
and place inputs and have outputs using the call library function.
Also in LV there is a new simulation toolkit that will allow you to
run simulink models from Matlab. Pretty useful actually. Hope this
helps.