The screen assembly for the Kindle Fire HD 8.9" consists of just a digitizer screen bonded to an LCD screen. The plastic frame is not part of this assembly. When replacing a screen assembly you generally remove the old broken assembly from the plastic frame to which it is glued, and glue in a replacement. If you acquired a new screen assembly that was already mounted to another frame, then you could have the compatibility problem you describe, because some 8.9" HD's come with SD card slot cut-outs in the screen frame and some don't. Unless you can forego the SD card feature you could then be in trouble, because you'll never remove the new screen assembly from its frame without breaking it; the glue is just too strong. My advice is to forget the SD card feature; you'll have to buy a whole new (overpriced) screen assembly to get it back. Just reassemble the Kindle using the slot-less frame; it'll work fine for most purposes! If you really, really need the SD card feature, then consider buying a new tablet...

The digitizer on the Fire 7" HD connects to the motherboard via a ribbon cable with a tiny ten pin plug mounted at its end. This plug doesn't seat very securely into its socket on the motherboard, so the engineers decided to hold it in place by a springy stainless steel clamp mounted under one of the motherboard screws. If you did not replace that clamp when you reassembled the Kindle, then the plug could have come loose. Also, the plug could have been damaged if it were plugged back in at an angle, or it may not have been fully or properly seated in its socket upon reassembly. If any of these conditions apply, then the 'touch' feature of the device will be lost. If none of the above conditions apply, then, believe it or not, it is possible that your new digitizer screen may be cracked. Even a tiny hairline crack in the wrong place can partially or completely interrupt the touch feature. Examine the screen very closely to be sure; sometimes cracks are very hard to detect. One way to test the screen for...

You can buy this screen on eBay from several vendors. Some vendors are local, some are from China or Hong Kong. The screen serial number is: ED097OC1(LF). (The second O is a capital "O," not a zero.) From a US vendor the screen will cost you a lot, maybe $75-90, and some try to get much more. From a Chinese vendor you can buy it for much less, around $45-50, but it will take a couple of weeks to get to you.

For the Kindle Fire HDX the digitizer and the LCD are separate screens. Unlike some of the HD models, the screens are not bonded together. Therefore you can separately replace the digitizer. Be forewarned, however, the access to and layout of the cabling in the HDX is poor and re-assembly is challenging!

As between the Kindle HD 7" and the HDX 7, the screens are completely different. You should keep looking; HDX screens are readily available on sites such as eBay and AliExpress. However, be forewarned: (1) in most cases, screen replacement is very challenging. You must be technically inclined and have the proper tools! (2) there are several models of Kindle Fire and they each feature TWO screens: a digitizer and an LCD -- be sure to get the correct screen, both as to function and model.

If the 40 second power button method suggested by Amazon does not solve the problem, then there is no easy solution.There are more difficult solutions, but you must be technically oriented, because you must be able to open the Kindle and mess with the parts inside. Be sure that you have diagnosed the problem properly: First, be sure you have cleaned the screen so that it is completely free of dirt, grease or fingerprints. Then check the integrity of the screen. If the digitizer screen should contain a hairline crack -- even a tiny one near a corner-- then the screen may have become partly or completely unresponsive to the touch. Sometimes a crack can cause a digitizer to lose only part of its functionality. To see if this is the case, rotate the Kindle (from portrait to landscape or vice versa) to shift the unlock 'swipe' to a different position on the screen, and see if you can wake the device from that new position. If so, then you will have confirmed that you have a broken digitizer. If not, then it is...

It is possible that your digitizer ribbon cable connector has come loose, or was not properly plugged back in at the time you reassembled your Kindle. This is a common problem because of the poor layout and design of the cable assemblies. If the digitizer is disconnected, then the LCD will come on when you press power, but it will go off a few seconds later since you will not be able to swipe the screen to 'unlock' the device from the power on screen. The solution would be to reopen the Kindle (i.e., remove the back cover) and properly re-seat the digitizer ribbon cable plug. This is the plug on the end of the long narrow ribbon which is folded over and held down by the mid-frame chassis.

The copper tape is 1" wide. You can buy it on eBay, but the minimum quantity is more than you'll need for just one Kindle. See, for example. this ad: http://www.ebay.com/itm/291524136308 which is running now.