Regarding BackGround Worker

I agree with the above comments, still, if this does not solve the problem, you could post some of your code here such that we can take a look.

If your method will access UI related properties, you need to use Invoke or BeginInvoke to marshal the call to the UI thread to make it thread safe. Note that the call mashalled to the UI thread cannot be a long time job or too frequently, otherwise, your UI still could be unresponsive.