trouble burning cd w/ samsung sh-223c and nero

newbie to these forums here, having unreasonable amount of trouble burning cds using samsung sh-223c drives and nero in various configurations. We are a media production company, so we need these to come out not only working, but have some other criteria must meet (no burn rings, etc). We had been using samsung sh-s183 and sh-223q drives and nero 7 ultimate without issue. We make 'masters' from a computer using that configuration and then make mass copies using burning towers. It looks like those drives are now discontinued. Tried samsung sh-223b and v. l drives and get burn rings. Also tried some Sony Optiarc (not sure version) and also burn rings. While these discs seem good and play, the rings are unacceptable for our purposes. Tried the v. c drive and this is where it got confusing.

Was able to burn a disc successfully, smooth burn, no rings. Played in a computer correctly (saw 23 3 minute tracks). When putting into a regular cd player (discman, car) it will see all 23 tracks, but only will play the first track which is 65-70 minutes. All other tracks will not play. Also, could burn 5-7 discs successfully, then the entire computer would lock up. This was tested on two different machines, one w/ clean updated install of Win XP Pro SP3 32-bit w/ different hardware. Both machines would occasionally lock up w/ the v. c drive and Nero 7. Tried the trial of Nero 9 full version, same results, the lock up and unable to play back in cd players. I then tried burning audio cd w/ Win Media Player, and that disc would play correctly in a cd player. But when tried making copies w/ a burn tower w/ sh-223c drives, same result of cd players unable to play all tracks.

We really just need this to work as before. We can't rely on hunting down discontinued drives to purchase (we go through a lot of drives). Thanks in advance for any thoughts.