a question in backgroundwork process

Hi ,

I am using a backgroundworkprocess which displays an loading form while doing some background heavy lifting in doWork. Here i came across one problem - I create an instance of RichTextBox and copy its content and paste it in word document. This causes my app to hang. Doing some Google i found out that in multi threading we cannot access windows control. So can any work around you guys can suggest for this? 

Thanks,

Ramesh