SONY DVD RW DRU-720A_JY08 power up question



I have a SONY DVD RW DRU-720A_JY08 on my WinXP Pro SP3 computer.
It’s about 2.5 years old. Lately , when I power up the drive (it’s an external USB device ) it makes a sound that I don’t like. The best way I can describe the sound , is that it sounds like a “groaning” sound.
The drive has been working OK. But last night it did fail to detect some new Maxell DVD+R discs I just purchased. But when I tried some other DVD and Cd discs it detected those just fine. So I figured that the discs were a bad batch.
Any ideas what the power up sounds may indicate ?