Hi Shah,
You might check out this
KB that explains the different reasons you could be receiving only parts of the data at a time. You might also check out the Serial examples that ship with LabVIEW. You can find them by opening LabVIEW>>Help>>Find Examples, this will launch the NI Example Finder. You can go to the search tab and type "Serial", this will bring up some serial examples that might be of some help.
What do you want your LabVIEW program to do when you press ctrl+k?
JenK