A system variable problem??

I'm pulling my hair out over this. Would sincerely appreciate input
from anyone who may recognize this, and know how to correct the
problem!

A co-worker is trying to edit a line of text within a block on a
drawing on our shared server, from his computer. The text for this
drawing is formatted as "Standard" style, where the font is romans.shx
and the BigFont is one of OUR company's customized shape files. The
radio box stating "Use Big Font" IS checked. We're both using AutoCAD
2007, on Windows XP
systems.

Using _eattedit, he edits/types in the following string:

[D[4"x 6"

The result looks like this:

PL1/4?x 6? (Our customized SHX file allows the PLATE and FRACTION
characters but the INCHES/QUOTES character is not recognized in this
instance. It's usually not a problem, however.)

FROM MY COMPUTER, I typed in the same string on the same drawing...
also using _eattedit:

[D[4"x 6"

.... and the result is what we want:

PL1/4"x 6"

So I compared what my co-worker entered to what I entered and I
noticed his quotes/inches (") looked italicized when I brought them
up in the text editor. But the Text Properties and Attributes appeared
the same. In fact, EVERYTHING in the Enhanced Attribute Editor looks
identical to mine, and as it SHOULD look. So I saw nothing that would
tell me what was different.

So next, I copied and pasted HIS (") from the text editor to paper
space, then I copied and pasted MY (") to paper space. I then selected
his (") character and looked at the Properties of the selected text...
and believe I found the problem. In the TEXT category, under
"Contents", his quotes/inches character (") reads:

{\fTimes New Roman |b0|i0|c0|p18;"}

It's being AUTOMATICALLY formatted/overridden as a Times New Roman
font! Remember, the drawing text is formatted to use another font
(romans.shx).

He is doing nothing differently than I would. And I'm editing/testing
the SAME drawing he is.

WHY WOULD THIS AUTOMATIC FORMATTING be happening on his computer? And
how do I "FIX" it??

Is there a system variable or some other setting/parameter that would
control this??? I'm tempted to believe there is.... because he tells
me this was not happening this morning. He went to lunch and when he
returned, this was happening. I'm inclined to believe he
inadvertently hit a combination of keys that re-set [something]. What
that
"something" is, I don't know.

ANYONE, please?

THANKS, in advance...

~Julie~