The drive will begin to run the self-diagnostic test. During this time, the drive will continue to blink green/orange in rapid succession. This process takes approximately 9 minutes to complete.
If the drive LED begins flashing orange in 3-blink cycles, then the disc you loaded is not a blank CD-R disc.
If this is the case, remove the CD-R disc, power down your system, and perform steps 9-12 again.
After finishing the diagnostic, the disc will eject if there is no drive failure detected. You have a working drive.
This is right from the Plextor website. Your drive has no blink codes so I would suggest checking to make sure your drive is in DMA Mode. Run a write speed test (speed read enabled) with Plextools or a transfer rate test with Nero CD-DVD Speed (preferably with a couple of different discs) Also a burst test with CD-DVD Speed should give about 40mb/s.