I also had the same problem, Cannon MV700i only recording sound. The veiwfinder, LCD sceen blank, VCR playback working fine. Contacted Plymcare by phone, they were very helpfull. They explained Cannon were aware of the problem and providing problem was ccd, would repair free of charge, as they bill Cannon. Posted the camcorder (over 4 yrs old) by special next day delivery and returned 3 days later, fully repaired. The only cost incurred was postage to Plymcare ( i paid just over £6 ).
01752 303 555
Send the camcorder to plymcare in plymton, plymouth. You will have to ring them for the full address but they will repair it and send it back by courier free of charge if its th ccd that needs changing which it usually is. I have just done this and it was back within 2 days.
CCD sensor is faulty ( this is the transducer which converts light into image behind the lens inside your camera ) has to be replaced and this should be done free of charge by the agent.
Usually answered in minutes!