I am having some problems managing some DXF and DWG files.

I'll give a quick professional background, so you know where to aim the replies. 

Professional Background:  Former C++ developer, physicist and NASA employee turned yacht charter captain.  At this very moment, I'm working on building our new charter boat. 

I have a master DWG and DXF file for the bulkheads for the boat (bulkheads are like walls inside boats that follow the curve of the hull).

I am trying to simply do the following:

1)  Open File

2)  Turn off all but one layer

3)  Zoom and Crop to show a small part of the single layer

4)  Save the cropped drawing as DXF of DWG

Easy, right?  WRONG.

I'm on a 2.1GHz MacBook running OSX.5.8 with a Gig of RAM

I tried installing AutoCAD for Mac but after a nice 4 hour download, it says, "your graphics card is not supported, aborting install."

I tried Solid Works eDrawings.  It opens the file beautifully and allows me to turn layers on and off and zoom.  It doesn't allow me to crop or save the files.

I tried DraftSight.  It shows a blank drawing when I open any of the files.  

I'm trying to get these files plotted 1:1 on a 3' wide plotter, but the printing company refuses to do the zooming and cropping, even with an offer of extra pay.  

Here's the thing:  I'm working 10 hours a day, 7 days a week on a project that will take me between 4000 and 6000 hours to complete (2 or 3 years).  I cannot afford losing another 10 hours to something so stupid. 

Can anyone help me understand how I can simply open, fiddle with layers, crop and save a DWG or DXF file on a Mac with the specifications listed above? 

I'd even settle for going to some kind of FedEX Office/Kinko's that has CAD workstations available.  Any ideas??

Thank you in advance for any help or advice.  

Thanks, John.  

I know it's an older computer, but there isn't any real reason to update it at this point, considering I don't work in offices anymore.  It's used for web development for our charter company, Quickbooks, email, browsing, etc...  Nothing too intense.  It's only used a couple hours a day, max.  

I did get it after about the 8th download though.  Here is the program I used, which is quit an excellent little CAD utility for what it is:

http://sourceforge.net/projects/librecad/

CADuntu

Figured I'd follow up here even though I finally found a solution, for those who might be stuck with a similar problem.  

Thanks for the offer of help.

http://www.librecad.org/

It's open source software.  It does everything I was trying to do and quite a bit more, actually.  Try it out.  It's open source, so it costs nothing.

I co-wrote the following CAD/CAM software when I was a C++ Developer: