Unfortunately when I went off to college in the Fall of 2000, I was a very stupid girl in letting myself be convinced by several credit card representatives on campus to apply for a credit card. One of these cards was a Discover card on which I was given a $1000 limit and allowed to exceed my limit at which time they charged me over the limit fees. This caused my mimimum payment due to increase and after several months of struggling to pay it, I made my last payment on May 2001 and subsequently let it go to collections.
Over the next couple of years I received letter after letter from a variety of collections companies claiming to be authorized to offer me a settlement on Discover card's behalf until October 17, 2003 when I received a letter from PDI Management Services stating that Discover had SOLD my account to them. As with the previous companies, I did not respond to the letter and they never took legal action. However, much to my surprise, on August 24, 2004 I received a notice of "order approving stipulation to indebtedness and entry of final judgment upon default" filed in county court by the lawyer representing plaintiff, National Asset Management, LLC stating there would be a final judgment upon default if I did not make payments on the account. In January 2006 after I defaulted on the stipulated payments, a judgment was entered by the court.
In looking back at my paperwork and finding that my Discover account was originally sold to PDI Management, was it legal for National Asset Management, LLC (assuming they bought my account from PDI) to file a judgment against me? If this was not a legal action can I file a motion to vacate the judgment citing this as the grounds? If however, the "current" owner of the account (no matter how many owners may have preceded him) is allowed to legally file, am I within my rights to request that they prove they purchased my account from PDI and if they cannot provide proof, use this reason in my motion to vacate?

As you say, you were very stupid... your arm I take it was not threatened to be yanked out of its socket... you took the card knowing you had to pay for whatever you put on it.
It was your decision also to go above the limit you had set yourself... so why the beef.

You made the debt... now either pay up or face the consequences. Seems to me you are just trying to get out of reponsibility for a debt you made.
If you wish to put it down to stupidity... like ignorance, it is no defense against what you understand the law to be.

Make payments... get this off your record for future loans... including a mortgage.

Well if you had appeared in court, you could have challenged a lot of things, including proof they purchases the account, At this point and time, no they have a valid judgement.