Inspiron 1545 doesn't recognize optical drive, other issue

My wife has a UK-spec (since she's British) Inspiron 1545 laptop running Vista Home Premium with all the latest updates.  Recently (not sure when, since it's rarely used) the CD/DVD drive disappeared from the system.  It doesn't show up in the Device Manager, nor does it recognize any known good bootable CDs on startup.  The drive itself works fine in another laptop, and a known good drive from the other laptop is similarly not recognized in the Inspiron. When a disc is inserted in the drive, the activity light comes on and the disc spins up as expected, but the computer never seems to recognize that it's actually there.

I have reset the BIOS, which is the latest available version, to factory settings as well as tried various combinations of boot sequence, etc.  When I press F12 for the boot menu when a bootable disc is in the drive, the optical drive isn't listed as a boot able option.  Thus, it seems much more than just a driver issue.

In conjunction with this problem, and possibly related, is that the SD card slot seems to also be hinky. She doesn't use the slot much but for the past few days noticed that her computer was taking an exceptionally long time to boot (long delay between the Dell logo and the Windows startup screens, with just a black screen and blinking cursor). After hours of troubleshooting, I finally discovered that removing the (empty) micro SD card adapter she usually keeps in that slot solved the slow boot issue.  We thought it was maybe a bad card adaptor, but I tried two other empty micro SD card adapters and both had the same effect.  A regular SD card in the slot works fine and the computer boots quickly as expected.  This is very odd behavior, because she's kept the same empty adaptor in that slot practically since the day she bought the computer and never had trouble until a few days ago.

As far as I know, nothing changed in terms of drivers or other software immediately prior to these problems appearing. BUt as I said, we're not sure how long the optical drive has been "missing" because it's rarely used.

Any thoughts?  Is there anything else I can reset, any magic buttons inside the machine to press, batteries to pull, etc.?  We fear the worst (faulty mobo) but hope someone has a solution we haven't considered.

Thanks,

Brent