Good to know. Is there some way of knowing which screw a manufacturer uses and also where can one find the right screwdrivers in the US (eBay?). Has anyone had personal experience with this?

I've been eying a full frame Nikon, but that's more of a long-range plan than something I'd do soon (although I'm sure Cameta would be more than willing to help my select a new Nikon like a 500 or 610). So for now, just going to have to sit tight and wait to get everything back. Hopefully not more than 2 wks but who knows?

Cameta put another lens onto the body and no problems. AF, exposure, all worked fine. Biggest fear was if they could not get off the lens, the repair bill from Nikon would be close to the value of the D7000. So far, my only cost has been shipping it the store and whatever Tamron might want to charge. However since the lens is under warranty, I doubt they will want me to pay for a repair and also Cameta is a big reseller for them and they are handling this.

Just got a call from Chris at Cameta. They were able to get the lens off (lots of wiggling but it did unlock from the body). Seems there is a spring-loaded tab that is used to set the aperture, however the mechanism is not working (spring may be damaged or missing) and so the tab was not disengaging. We all thought it might be a loose screw on the ring, but this was even a weirder problem
In any case, Cameta is sending the lens to Tamron to get it fixed. In fairness, Cameta has never seen this type of problem but Chris said that Tamron does excellent repairs to their lenses.
So for now, just have my cellphone camera and wife's Sony point and shoot. Luckily no big travel plans until Xmas so everything is looking up.
Again thanks to you all for your suggestions but even if I had gotten the lens off, there's no way I could have fixed this problem.

Thanks, but everything has been shipped to Cameta. I did a look-around before it went out. The only things that the Tamron has on the side of the lens are AF/MF and VR switches. Otherwise I have to assume the culprit is buried in the mounting ring but since it could not be removed, no way to be sure.
Once I get the final diagnosis so it can be shared with others. I looked at other lenses (Nikon and Rokinon) and they all have some kind of screw mechanism to attach the ring to the lens body so it most likely the same for the Tamron

The lens can't be removed from the body so this really isn't an option. Also if the screw is stainless as most are, then a magnet really won't help. Plus the distance from the ring to the lens is probably around 4" so nothins short of a magnet from an MRI machine would be strong enough. In any case, the camera and lens are on the way to Cameta. I trust them as I have bought all my cameras, lenses and flashes from them and they offered to help take care of this.
The real lesson I'm taking away is that every few months, I should/will take a jeweler's screwdriver and make sure the screws on the lens mounts are all tight and flush to the ring.

I bought it lasst year. Still covered by Tamron warranty

No secondary insurance, just warranties. Most likely will have to pay Nikon to remove the lens unless Cameta's tech dept can do it. From all the comments, this looks to be an issue with the lens and I'm holding Tamron responsible for that.

Sounds like the only way to get the lens off without damaging the camera is to have it done by someone who knows how the camera is assembled (i.e. Nikon). Sending the camera-lens back to Cameta today since they offered to handle this and I don't want my equipment damaged to the point of not being able to be used.

Hi all. Thanks for the advice. I did call Tamron, Nikon and Cameta. Cameta will try to remove the lens but if they can't, they will send it off to Nikon. Tamron will not touch the D7000 for obvious reasons but will fix the lens. I am not going to try to remove it myself since that would void the Tamron warranty. It could very well be a screw that cam loose, but I'm not going to try to fix it myself since I can damage the lens and camera and have no recourse.
Will let you know the outcome and whose fault it was for all this mess. Bottom line is the camera works now and I want to keep the mechanical problems to a minimum so I'll let the pros handle it from here.

So far both Tamron and Cameta said they never heard of this either, but both are leaning to a lens issue. Cameta said to send it them and they will try to remove the lens. If they cvan't they will send it to Nikon on ny behalf who will probably have to dissemble the camera to remove the lens. Tamron will fix the lens as it is still under warranty.

FYI heard back from the tech dept at Cameta. This is the 1st time they have encountered this but the concensus is that the problem is with the lens, not the camera. Doesn't help me much, but Cameta suggested I send the camera and lens to them to see if they can get it off. If not, they will send it to Nikon and most likely Nikon will have to take the camera apart (lucky me!)

Hi all. Was on vacation and this problem developed suddenly. Previous photo (observation point on Mauna Kea on Hawaii and yes, it is beautiful there) was fine. However the next shot everything went nuts. Could barely see the image through the viewfinder, could only see 1 focus point, and when I went to change the lens, it would only turn ~ 1/4" before it stopped and would not go any further to remove it. When I turned it back to reingage, it locked in fine, but the problems persist (low light, only 1 focus point, and cannot remove the lens). Autofocus, exposure are all OK, but the lens won't come off and viewing an image is almost impossible.
I called Tamron and while they said they would certainly take care of the lens (warranty), they would prefer it was off the body since they are not responsible for that. Would prefer not having to send the camera and lens to Nikon since they also will not take responsibility for the lens. I did call Cameta ( I get all my stuff from them) and am waiting to hear back from their tech person but they send all their repairs out. I thought about bringing it down to Mack (I'm in NJ and too far from them) but then lens is still under Tamron warranty.
I don't want to force it off but also don't want to see a repair bill that's bigger than the cost of the camera. So, if anyone has ever experienced a lens-camera problem like this, please let me know what you did to get it off. Any and all suggestions gratefully appreciated.

Clearly, too many people rely on Homer Simpson as a life role model. :)

I'm sure the police have already done this but there should be a wealth of information about the gear's owner in that box including photos and fingerprints all over the place. Also as someone pointed out earlier, Leica may have info on file and well as any lenses the owner had bought new and registered. I can't imagine anyone with this equipment not registering it (unless, of course, they stole in the first place).