Hi, I have a disk with Lightroom 1.0 that I have installed a couple of years ago and have been using for a while. I had it backed up several times. I recently had to reinstall my WIndows XP and with it reinstall everything else. When I installed the Lightroom CD it prompted me to download the 1.4.1 update, which I did. And then I tried to open the backed up file - it turned out the backed up Lightroom is 2.7!!! and it cannot be opened with my older version. I am at a total loss. I tried to install Lightroom 2.7 but the serial number I have doesn't work for it. I can't remember at all how my Lightroom got upgraded to 2.7 from 1.0 since I have always had only one disk and one serial number. What can I do now (for free) in order to make the two versions work together and to open my backed up files and to continue using 2.7 (because I am used to having the paintbrush tool and the crop tool under the develop function, and they are not available in Lightroom 1.0). I am sorry for the lengthy description but I am totally ignorant about updates, new versions, etc.
If you've been running 2.7 for a while, you must have used a valid serial number when you first installed it. If you have no distribution CD, then perhaps you purchased version 2 from Adobe's website and were given a serial number in your email at that time. If you save such emails, you might still have it available.
If not, Adobe's web site keeps serial numbers for all registered products, and you ought to be able to retrieve it there.
If all the above fails, you'll need to contact Adobe's technical support and talk them into giving you a serial number that works.