Opening existing Word Office Pro Plus 2010 document on a new computer with Word Office Pro Plus 2010 results in *some* of the text becoming "corrupt"/garbage

Question

The source file had this text in a section I call "LANGUAGES":
Arabic:  Hello (Peach and health) = Salam-Alekum 
or Salam al salad; Thank you = Shokran; Please = Men-fad-luck; Good bye = weh-don
Bulgarian: Hello = dra-vaht; Goodbye = chow-chow; Thanks = wah-go-da-rhia;
 (s:Sanya, (DigitalStar/E&E Electronics, DTV converter box)
Chinese/Mandarin:  Running dog (servile follower, lackey) = zougou; This = jeige (jay-gah); That = neige (nay-gah); Hello, Mr. Lin (politely) = Lin-chenzin, ne how; Thank you = Xie xie (shay-shay); You’re welcome =
boo-kai-she
Czech:  Hello = ahoj (ah-hoe-ee); Thank you = děkuji (de-quoy-yeh); You’re welcome =
není zač; Good afternoon = Dobré odpoledne;
Good morning = Dobré ráno; Goodbye = 
sbohem; Goodbye for now = sbohem prozatim; Yes = ano; No = ne; Yes sir = ano pane (ano paanay); Have a nice weekend = Hezký víkend!
Farsi:  Havij = carrot
After making a copy of the file, renaming it, and starting to use it, I noticed the above section looked like this:
Arabic:  Hello (Peach and health) = Salam-Alekum 
or Salam al salad; Thank you = Shokran; Please = Men-fad-luck; Good bye = weh-don
Bulgarian: Hello = dra-vah-DÅ7¢£8¿i¾A\ÅïÕÒb·#ªp¡€^žÏM–ehÂ*á‑L[Â¥!Ü"»¿¥g©P2<©\         
Y5FUƒŽƒÄœý>ù4Õ
çÂ7¬ê=Ë"i»°ù‹þñ
%¦ðèbjS¬Ö
ÈuzdºD,%z¥.-
 á©ÊˆšHíÅ\kêämݳ¡jíúSƒ©@Žu <i
b€ÕV~Y©Ó·Š€§¥[Ò]õy›Y°¹8U¾Ÿ²ää';z8©ŒN´«§6–‡0¥Ÿºns‚† ;ËÁ_$
y°hGëÀ¾­-Ô9ÕÕb'_Ü­ª~Ð4®lÍnròŒÚHðѐ–ŠZ+pT’œd0yÙDØ®±,â;QäO‘Q#¤¾šÆ™b
͵c‡†Ý6#K–EPu¿lÉPUZC^»F+óR¯t”âx<Yñ`gëèø‑çg/Ðp“ð5ÓH˜âi'ówSÛǨêÔ3úè! ˆ%­vȐf>էȖ*=ZÒ±ª děkuji (de-quoy-yeh); You’re welcome =
není zač; Good afternoon = Dobré odpoledne;
Good morning = Dobré ráno; Goodbye = 
sbohem; Goodbye for now = sbohem prozatim; Yes = ano; No = ne; Yes sir = ano pane (ano paanay); Have a nice weekend = Hezký víkend!
Farsi:  Havij = carrot
In another section of the source file, I had this URL to a Yahoo Finance stock listing:
http://finance.yahoo.com/q/cq?d=v1&s=RIMM%20DRR%20NDN%20GMCR%20DF%20V%20ACN%20MOS%20SHLD%20BUCY%20NTGR%20CPRT%20EEM%20DIA%20CME%20mkl%20t%20spy%20goog%20yhoo%20uis%20fnm%20ge%20ko%20MCD%20eln%20emc%20bvf%20abt%20wpi%20agn%20frx%20sfd%20amd%20cnp%20d%20ed%20eix%20celg%20qcom%20nt%20peg%20ppl%20bby%20flex%20cof%20asyt%20proxq.pk%20nok%20fe%20sns%20ibm%20spg%20wlp%20bfly%20brka%20brkb%20zmh%20cmi%20kg%20vrx%20amt%20twx%20ctxs%20sgp%20dox%20cmvt.pk%20elx%20xel%20aapl%20amzn%20jpm%20bsx%20mdt%20duk%20se%20csco%20jnpr%20dell%20ebay%20lly%20hpq%20hurc%20intc%20inin%20lvlt%20mck%20msft%20onb%20orcl%20scln%20smtk%20wmt%20tgt%20brwix%20obehx%20qqqq%20ssdsx%20csvfx%20scdgx%20ktcsx%20t%20obhex%20slafx%20sjpnx%20scinx%20a%20adsk%20alu%20arba%20atahq.pk%20coms%20palm%20rwc%20vrcc.ob%20dis%20ila%20novl%20utmd%20rprx%20nrom.ob%20obehx%20obhgx%20obfox%20sctgx
In the copied file, it now shows this:
http://finance.yahoo.com/q/cq?d=v1&s=RIMM%20DRR%20NDN%20GMCR%20DF%20V%20ACN%20MOS%20SHLD%20BUCY%20NTGR%20CPRT%20EEM%20DIA%20CME%20mkl%20t%20spy%20goog%20yhoo%20uis%20fnm%20ge%20ko%20MCD%20eln%20emc%20bvf%20abt%20wpi%20agn%20frx%20sfd%20amd%20cnp%20d%20ed%20eix%20celg%20qcom%20nt%20peg%20ppl%20bby%20flex%20cof%20asyt%20proxq.pk%20nok%20fe%20sns%20ibm%20spg%20wlp%20bfly%20brka%20brkb%20zmh%20cmi%20kg%20vrx%20amt%20twx%20ctxs%20sgp%20dox%20cmvt.pk%20elx%20xel%20aapl%20amzn%20jpm%20bsx%20mdt%20duk%20se%20csco%20jnpr%20dell%20ebay%20lly%20hpq%20hurc%20intc%20inin%20lvlt%20mck%20msft%20onb%20orcl%20scln%20smtk%20wmt%20tgt%20brwix%20obehx%20qqqq%20ssdsx%20csvfx%20scdgx%20ktcsx%20t%20obhex%20slafx%20sjpnx%20scinx%20a%20adsk%20alu%20arba%20atahq.pk%20coms%20palm%20rwcþØ9—=t‡†|¤wžÌèûÛÌo¯€[Ú
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Anyone have any ideas on what is causing the corruption and how to prevent it?
BTW, if I re-copy/paste the corrupted section from the source file, it appears correct...for awhile...and, then, later, I'll notice that it has become "corrupted" again.  I have *not* compared various corrupted sections
to see if the corruption texts are identical each time. 
Michael

Answer 1

Thanks for the reply, Melon. 
I disabled the only 2 Add-ins that were present - [COM Add-Ins > Sharing Add-in for Microsoft Lync 2010] and [Actions > Instant Messaging Contcts (English)]. 
This did not fix the issue.  After they were disabled (and they currently still are), I copied back un-corrupted text from my good source file and the text at the end of the document has become corrupted again.  Except for the ][Languages] section,
which is much further up in the document, the corruption seems to be consistenly near the end of the document. 
I tried to highlight some of the corrupted text and change font, as suggested, and the text just becomes corrupted text in the new font.  :-) 
I notice that, if I start selecting text (starting from a paragraph mark above the corrupted text - I always keep hidden formatting symbols turned on), as I "arrow down", the "selection" includes lines in blocks lower down -- that is, the corrupted text is
repeated down the page. 
Since this may not make sense, I'd be glad to upload samples of the good, original, source text and the corrupted "versiion" of it. 
I still need to test the file on one of my computers at home. 
Thanks. 
Michael