Multi-threading?

Question

Hello, i have a C# Windows MDI application that opens up to 8 child forms.  Each form has a start and stop button to read some data and graph it.  If I open up all 8 child forms and start the graphing the application becomes unresponsive, meaning I cannot move or resize any of the windows or change any of the settings for the graph.  I think it is because all of the reading and graphing is done in the same application thread.  Does anyone have any suggestions for making this work better?  Ideally I should be able to have the graph reading and freshing and still be able to move the window around.  Also, the graph is a user control which combines the reading and graph as 1 control.  This is bacause the data is send via a bluetooth connection and makes maintenance a lot easier.  Thanks.