Authorized computer still not playing songs

Hello,
I had to upgrade computers. when I went to transfer all of my songs I lost some and some still won't play. The songs I lost were because I "didn't have rights". Thanks iTunes. The rest of the songs transfered OK, or so I thought. When I went to load some songs onto my iTouch, a few of them needed "authorization". I have gone through this quite a few time, the computer is authorized but the songs still will not transfer to my iTouch or play on the PC. These were songs that were purchased from iTunes on the old PC and played fine until I upgraded computers. The part I do not understand is of the 60 or so songs I purchased from iTunes using the old computer, it is only a hand full that will not play. Needless to say, I need help getting the handful of songs that would not authorize the first time to become authorized.

Can someone help.
Thanks in advance!
Gary