Which version of the program are you using and on what operating system?
Is this gap on Video 1?
Is there any video or audio on any other track that might be keeping this from being a true gap in the entire timeline (and not just on that track)?
I am using Windows 7 Yes on Video 1
There is nothing on the sequence to delete but some other tracks are used forward
Please post a screenshot of you timeline.
Which PE and OS are you using?