My Garmin is full so cannot update any more, Is it possible to delete everything and reinstall a new map, think its 2009 that is on now.

Check if there is any bloatware on your Garmin. Mine came with things like language and city guide demonstrations on it, which can be deleted. Also check what languages and icons you have installed as removing some of these can also save space. The only other thing to check is do you have an SD card slot on the unit as you can install updates on to these.

Which model is it? 

It should have a slot for a micro SD card for memory expansion depending on the model.

 

Check the manual.