I have been dealing with Adobe this morning via "chat" regarding the problem that I had initially on my desktop with receiving a message that stated my serial number had been used on the maximum number of computers. I explained that this may have been due to having to replace the hard rive on the desktop. I was told that this problem had been fixed whilst we were on line and to resart Lightroom, which I did, but everyime I restart Lightroom the home page comes up and them i receive the message at the top keft hand of screen that it is not responding. i was then told to reboot my machine, which I have done, but it has not cured the "not responding" problem on my desktop. I then checked my laptop, which is the only other PC that I have Lightroom installed on, and that now gives me the "maximum number of computers message. Please help, as i ma in the middle of preparing a Photobook.
Please refer the below steps on the desktop machine to fix the not responding issue.
Go to Lightroom Preferences from the Edit menu
Click on Performance tab
Uncheck the Graphics Processor
Let us know if that helps.