while opening the drawing error showing access violation reading 0x72d9a30 in autocad 2010. how to fix these erro,r help me.

What were you attempting to do when the error occurred?Does it happen in every drawing you work in or just a particular drawing?AutoCAD 2010?  Have all updates been applied?

It happening particular two drawings only. How to apply updates?

Download them from the AutoDesk website.Are the drawings 2D or 3D?Have you purged and audited the drawings?

It is a 3d darwing. I have audited the drawing, no errors found.This drawing was created in 2004 version and iam able to open in 2004 and 2008 versions.Only in 2010 version it showing error. This drawing contains more than 2,35,000 EntitesNow iam using 2010, 64 bit trail version. Is there any entity restriction in trail version. 

None that I know of why?Did you purge the drawing before auditing?