Rizone DVD Repair is a simple tool that will fix common CD or DVD drive problems at a click.
If Windows no longer recognises your DVD drive, for instance, or sees that drive but doesn't think it's writeable (it's identified as a DVD-ROM) then the program may be able to help. This issue is usually down to faulty filter drivers, and DVD Repair will delete those references, hopefully fixing the problem (though you may need to reboot first).
Of course if the issue isn't related to your filter drivers, then using DVD Repair may cause problems in itself, as whatever application installed those drivers may no longer work correctly. Use with care, and ideally create a system restore point immediately before running the program, so you can recover the original driver settings if DVD Repair doesn't help.
As a bonus, the program can optionally restore your autorun settings, and try to block autorun.inf files from running at all. This can be a mild inconvenience - you'll have to launch disc setup programs manually from now on - but will also improve your security, as it prevents software from running without your permission. (You don't really want your PC running unknown software on whatever USB key is plugged into it, do you?)
An easy-to-use portable tool that will solve many odd DVD drive issues. Though beware, it can also cause some of its own - back up your settings with System Restore before you run it