I"m using a HP 933 Mhz/1024MB SD ram computer. The DVD-RW drive is a SONY DVD RW DRU-510A. It has been very reliable when I had a P4 2.8 (no longer functional), but now that I moved it to the P3, the failure rate of DVDs has plummetted to say, 90%

I run simulations all the time, and often it fails. So I switch dvds, and it usually passes the simulation, but the burn process fails. I am using Nero to burn data dvds. What could be the problem?