This file is Unknown
and I need to open. ---->>> Lakewood scan.dwg   How can I open it
?

It's a DWG file so first I would try opening with AutoCAD.  If that doesn't work then I'd use DWG TrueView.  What program was used originally to create the drawing?  You do know that AutoCAD-clones can save to the .DWG file format don't you?

This AutoCAD
feature was added in AutoCAD 2006, when your AutoCAD software suddenly
crashes due to hardware malfunction, power failure or any other cause leading
to its abrupt closing then AutoCAD will show drawing recovery manager next time
you open it.

This recovery
manger provides a simple interface to locate autosave and backup files without
manually searching them over your system. Drawing recovery manager will only
appear in instances of sudden system crash, you can also open Drawing Recovery
manager from

Application
menu>> Drawing utilities >> Open the drawing recovery manager

When you begin
new session after system crash you will be welcomed by drawing recovery dialog
box.

Close this
dialog box and look towards the left of your drawing area to locate drawing
recovery manger palette. You will find a specification tree with autosave and
backup files in the list, click on files you will see their preview in panel at
the bottom. Double click drawing which you want to recover and you can now
continue with your work.

Or you may visit http://communities.bentley.com/products/microstation/w/microstation__wiki/2939.recovering-corrupt-dgn-and-dwg-files-cs

bert:  Do NOT follow any advice given by aidenburke and do NOT click on the link.Think about it.  Why would someone purportedly trying to help with an AutoCAD-related problem ask that you click on a link for Bentley Microstation?