hello allI'm quite new in autocad and I got some issues.When I open a dwg file, although there is 5 layers in the file, I can't see anything on the display manager. just "Map base" and "defult". and of course - I cant see the table data of any level.After looking for a while on the web, i guess it has something to do with 'blocks', perhaps its all together in a block.How do I break it ? 

Did you check to see if you had any Frozen layers first?Blocks aren't "broken" they are "exploded".  Not necessarily a good idea unless there is no other choice.

Thank you.You can see in the attached picture.http://img820.imageshack.us/i/unledph.jpg/It's not Frozen, but still - doesnt appear at display manager

Can you post the file so someone here can take a look at it?

Hello sir.I really can't, It's a private file that belongs to my company. sorry for that. Any Ideas ?on another subject, is it possible to unite a few DWG files together ? that every DWG has his own layer ?

Then post just a portion of the drawing file and not the whole thing.

"...is it possible to unite a few DWG files together ? that every DWG has his own layer ?"The only way I can think of doing this would mean that each separate drawing would be done entirely on one layer.  If you had 10 drawings you want to combine into one then you would have 10 layers.  Ex. - Drawing #1 - Layer 1.  Drawing #2 - Layer 2.  Drawing #3 - Layer 3, etc., etc., etc.  Got it?

For splitting a DWG file into individual layers you can use our LAY2DWG utility (see Download and Tips). Merging them back can be done using INSERT (explode the contents after insert).

Neat little utility but doesn't the OP want to take multiple drawings, insert them into a single drawing and have each of those drawings on its own layer?