Help - stuff dissappearing from Autocad 2005 Drawing

Hoping that someone can offer some advice on this...

I have a drawing that includes items imported from a .pdf document.
Everything worked fine when I originally did the drawing. Now, several
months later, I've got a new computer running vista. AutoCAD 2005 installed
no problem but when I open the drawing up, all of text has was originally
imported from the PDF has disappeared. In addition, several new layers are
there that weren't there before and the layer that originally held the .pdf
items is now split between several layers. I've tried to consolidate the
..pdf stuff back into one layer, by moving all the various bits to a single
layer but when I try, the bits from the source layers don't show up in the
target layer. I'm stumped!

 

It sounds like the drawing is really modified, but could this be a
video card issue? I've read that Vista has problems in that it only
runs the microsoft's proprietary Direct 3D system, and not the Open
GL.

The only other thing I can think of is that the PDF imported stuff in
on an Xref which has changed.


Joe Dunfee