Plextor 708a 1.06 destroys my drive!

4 days ago…i bought a PX 708a which has the firmware 1.04 in it…i upgraded to 1.06 immediately…and the drive could NOT read 99% of my CDs. I tried every different kinda of DVDRs, CDrs, etc…and 99% did not work…the drive gave me a led indication that it could not focus properly for the media. So i returned and got another one. This time…i didnt not upgrade right away and it worked fine…i still thougth that my first drive was damaged what i had gotten it…and today…i upgraded my second px 708a and BANG…it behaves the same way. I tried to downgrade back to 1.04, but this time it tells me that it cant read the TOC or cannot focus on a cd…

Has anyone had this problem or am i full of bad luck?