autocad files

how do u know what version of autocad the file is???

If you open a dwg with Notepad, at the beginning of the file it should have 'AC1021' or something similar. the last two numbers tell which acad version it was last saved. 21 means acad 2008.

thanks but it didnt work...

Quote from http://www.mossdesigns.com/cadzette-v1i25.htm

To determine the version of AutoCAD that created a particular DWG or DXF file, open the file as a text editor (save DXF files in ASCII text format first). The first six bytes of a DWG file identify its version. In a DXF file, the AutoCAD version number is specified in the header section. The DXF system variable is $ACADVER. Here are the version identifiers for the various releases. Note that more than one release uses the same identifier when the drawing format remains fully compatible.

• AC1018: AutoCAD 2004
  
• AC1015: AutoCAD 2002, 2000i, 2000
  
• AC1014: AutoCAD Release 14 (Release 14 sample
  
• drawings use AC1013)
  
• AC1012: AutoCAD Release 13
  
• AC1009: AutoCAD Releases 12, 11
  
• AC1006: AutoCAD Release 10
  
• AC1004: AutoCAD Release 9
  
• AC1002: AutoCAD Release 2.6
  
• AC1.50: AutoCAD Release 2.05

Do not modify the file in Notepad or you may corrupt the drawing file!

I always use the above method but if you look at the startup screen after opening a file it may say "opening a 2007 file"

Check out this free download of a .dll that will return the version of an AutoCAD drawing in your Explorer window even if you do not have AutoCAD loaded.

http://www.cushat.co.uk/dc/