On Windows click the start button and type into the search box:
%AppData% and hit return. Then navigate to:
(Substitute your own user name)
Inside the Lightroom folder look to see if you have a LRREG file; if so right-click on the file:
Lightroom 5.0 Registration
Choose Open With and select Notepad or click the Browse button and find notepad.exe at:
When the LRREG file opens in notepad you should be able to see your serial number.
On Mac OSX launch finder and hold down the Alt (Optn) key and click the Go menu and choose Library. Navigate to:
Right-click (control-click) on Lightroom 5.0 Registration
Choose Open With Text Editor
Have you got Show hidden files enabled? If not, enable it under the View tab in Folder options, and see if the file appears.
Tha show hidden folder was enabeld. You can see in the picutres below. I have talked whit Adobe and they only agree to help mee if I can provide a payment confrimation or order number. I have alredy checked my paypal accunt but I have not finde the payment, I will try whit my credit card .
In the mean time I can not get my key.
Hopefully Adobe staff can help if you find a credit card receipt as you have most of the serial number with the exception of the last four digits. Good luck.