I was installing AnyDVD 5.6.1.1. It installed just fine and wanted to reboot. No problem, reboot the PC. (XP Pro, SP2)
System reboots and I get error messages from Nero (v7) and some Pinnacle DriveCheck (or something, likely from my Studio 9 install). I don't recall which piece of software gave the first error, but it went something like The upper limits and lower limits for your DVD Drive in the registry have changed. Continuing may cause your drives to stop working. Do you want to continue? So, thinking "eh, probably just some silly run entry in the reg that Nero installed and can be ignored due to the nature of what AnyDVD does. It's probably just some overly safe message for novice users." So I go ahead and continue.
Then another message pops up. I think it was from the Pinnacle entry in the run section of the reg that said something about a drive (DVD) error. Again, I just went ahead and rolled with it.
I go into My Computer, and WHOA! No drives! That's not good. So I check Device Manager. Both my drives [BenQ DW1640 & LG GSA-4163B] are sporting the yellow (!). . There's also another entry which I didn't recognize ("GS7257K AUE174W Scsi CdRom Device") which has the (!). Also, my processor is now flagged (!)AMD AthlonXP+ 2700.

SO! I reboot again. No drives.
I remove the drives from Device Manager, reboot. No drives.
I uninstall AnyDVD, reboot. No drives.
I put on the most recent nVidia nForce mobo drivers. Reboot. No drives.
I physically disconnect the drives, boot up, (no drives of course), shutdown, plug 'em back in, reboot. They are back in Device Manager with the (!), but not in My Computer (nor being recognized by any apps).
I reinstalled Nero v7 and the newest 7.1.x patch/demo/update/BS hoping it would correct whatever it was. Nope! No drives.

Anyone? Anyone at all? Bueller? Bueller? I'm DOA right now, and it sucks. It's going to be a loooong weekend I fear...

Evolution2001,
Why don't you try uninstalling AnyDVD, then hopefully you are using XP restore, select a restore point before the time you installed AnyDVD.
This will not fix your software conflict but at least you should get your drives back and we can work from there. I would start by disabling Pinnacle if it is present in Msconfig startup items. I don't know anything about Pinnacle but most people don't have issues with Nero UNLESS YOU HAVE INCD installed. If you do uninstall it and save yourself future aggravation.

Personally I don't use System Restore because it has failed me in the past and is now disabled. I suggest all computer owners invest in a drive imaging program and back up ypur system with an image. I can't tell you how many times it saved my butt. I'v done over 200 restores from images and never lost a file. You can have your system back in minutes rather than countless hours spent troubleshooting or worse yet a fresh install.

Thx, ItzBin... I just finished a restore point before I came back here. I'm just going to keep updating my initial thread. That way, it'll be an easier read for everyone.

OK, I got a "30 minute edit after posting, limit reached" smackdown. So here's the update. (Admin, feel free to put it under my original post as I had intended...)

--------------

Update #1
I saw that AnyDVD created an Restore Point, so I figured I had nothing much to lose by giving it a shot. The reference points did show all my activity today (in/un/reinstalling AnyDVD twice, Applying Nero patch, etc). It also happened to have a restore point from yesterday. Why, I don't know. But since I've had nothing major yesterday, I chose that one. (This was my first time using System Restore). So I choose yesterday and the system does it's thing..blah blah blah...it reboots. First thing that pops up is this:
Pinnacle Driver Check detected problems with your driver settings. Would you like to fix these now? [Yes] [No]
Well, before I choose anything, I check Device Manager. Drives are still (!) but at least my processor shows normal again. I close out Device Manager and click on [Yes], to which it quickly responds with the unhappy message "Your driver problems have not been fixed. Please contact your system administrator." [OK]
So I figure...ah well, what's another reboot at this point??? So I reboot.
System comes back up. No Pinnacle message this time. Hmmm.. I check My Computer. Holy Shiite! I got my drives back!!! And everything is peaceful again in Device Manager.

So what's next? Being the sick and twisted individual that I am, I'm going to do it all over again for the reasons of knowing exactly what messages I got and from what app. This way, there's documentation of it for everyone should it happen to them. (Apparently I don't get enough tech work at work, so I need to come home and break my own computer here...that's just kinda sick...)
And I'm off!...

------------
Update #2
..Well, ain't this a strange one? It installed just fine this time.
Hmmm... the only things I disabled in the startup via MSCONFIG were:
nwiz -> nwiz.exe /install (part of nVidia's mobo chipset)
updreg -> C:\Windows\updreg.exe (part of Creative's Audigy registration harrassment)

Maybe the nwiz had something to do with it? Anything that tweaks the bios or registry could cause these issues, but that wouldn't seem like the culprit to me. I'll re-enable it, reboot, and see what happens.

Update #3
...I have no idea. I renabled everything in the registry, like it was before my initial install, and everything is working just fine. Or at least as far as there being no obvious errors on my system right now. Everything appears to be functioning as normal.
I guess stranger things have happened!

Evoulution2001,
Happy to hear you're up and running again. It appears it's something in Pinnacle that doesn't agree with what AnyDVD is trying to do.
If it ain't broke, don't fix it, just be glad it's working properly again.

Computers are unpredictable and behave strangely at times, so try not to waste too much time figuring it out.

Just one question, did you uninstall Any DVD as I suggested before doing the restore point from yesterday? If you didn't tha's why you got the error message from Pinnacle. If it's not on the machine Pinnacle should not have displayed an error message since that the state the computer was in when the restore point was created.

Happy Burning

just wanted to point out that nwiz.exe is part of nVidia's display driver software, not the nForce board - anyone with a nVidia vid card has this (or has disabled it)