Cynthia,
Why don't you call or e-mail your state PTA and just see what the status is? Why guess? You don't want to find out later that there was no official disbanding.....
1. Your new PTO and the old PTA are entirely separate, so I don't see any problem at all in starting up the new group. That's #1.
2. If the old PTA is completely defunct, meaning no officers, no dues and no assets for the past couple of years, then I'd wager it's been basically disbanded by default by your state PTA. At the very least it's certainly a unit "not in good standing." But, again, that doesn't matter relative to your new PTO. The new group is entirely separate.
Going forward the key is that you (and hopefully some others) want to get parent involvement going again. Good luck -- it's worth the effort.
I want to start a PTO at my school, but I have a problem the old inactive PTA. They have not been active for 2 years and while some say they disbanned, others say they didn't officially, and all I want to know is does it matter? I don't want nothing from them. I just want to start a whole new PTO from scratch.