Clam shell

[Eurotrash]

I have a 1997 Boxster which only has 35K miles on it an is stored in a climate controlled environment. Recently took it out for a nice 250 mile drive which required the top to be moved up and down several times during this days trip. Once home I placed the top up for the night and there was no unusual noise and it functioned as always, flawlessly. Next morning we went for a small trip, Put the top down with no problems. Parked in a shaded area for the day and drove home. I put the car back into storage and when I went to put the top up, WHOOPS. The right side clamshell popped out of it's slide. The left side would not move at all. I was able to push the button to lower the shell and it appears to be level. I tried again and the same thing, the left portion would not budge. In the down position the dash lights show that the roof is down. so I am thinking that all microswitches are doing their job. The motor does not sound strained and both sides of the V rod and connectors are attached. Any suggestions as to what might cause the left side not to operate. What should I test and check for? Thanks in advanced for any help.