If the device is found in the h/w manager section as you state it has a yellow flag. Then install the device when you use the "update driver" button, click on it and then make sure you can then direct it to your disc or source of drivers, rather they be Win98 or XP, etc.. It should find what it needs upon "highlighting" where you direct a source of proper drivers. However, I don't think any Win9x drivers are going to work, IMO. When it can't be found or allow itself to be driver updated, then you have an "orphan" device, its time to move on. But try anyways.
What you could do is use a newer int. DVD drive, swap it for the current DVD drive int. to that USB case. -OR- upon removing that old DVD drive what model# installed truly is, it maybe a Sony or Hitachi based, etc. DVD drive from its decal/sticker. You locate driver for that model# and hope ti works. If as you say, it works on Win7 with the post you found, then the instructions should be clear. From what i read it offers no real clue why it worked, though someone offered it did. If it does work regardless, then you have some conflict preventing it from fully installing, besides the driver issue, maybe USB based one or power. Use a rear USB port.