I had left the machine dubbing a dvd-r during the night. (5 episodes recorded in XP then dubbed in FR to fit.) In the morning I went to Disk Management to enter a disk title. On pressing Stop to save the title the machine suddenly switched off itself and went through it's power down routine. When off and displying Bye it turned itself on and went through the self check. However it wouldn't respond to any commands and turned itself off then on again. This time it did respond as normal to the remote. However the title I was entering was gone and when I tried to enter it again it kept saying the disk was protected. Also I could not finalize the disk - it says finalize time is 0mins and then ended with "Cannot finalize". Another strange thing - I dubbed a first disk before leaving it dubbing a second one overnight and on testing I cannot play this disk in my Sony DVD player. However all previous dubs work fine. Could this be related to the machine glitch? The machine appears to be working as normal - I can record to the HDD and I will be testing dubbing again later tonight. Should I be concerned about this? It seems a problem with the machine than the disks which are Taiyo Yudens from SVP. Never had a coaster with them so far.
I've had the same problem crop up when using a brand of disc that it doesn't like. It can be a bit picky with certain discs. I used a whole load of Datawrite red 4x version 2, all without problems, but when I bought some version 3 discs I had a nightmare. Most of the discs wouldn't burn at all and some failed at the titling stage as you described. The reason it keeps restarting is that when it finds a dodgy disc in the drive it thinks it has crashed. That's a small failing of the operating system in my opinion - it should be able to start up and just tell you that the disc is dodgy. I would try a different brand of discs if I were you. I haven't had any problems with my current batch. As for the disc which won't play in your Sony, I suspect that the Sony just doesn't like un-finalised discs.
Subsequent dubs on the same type disks (Taiyo Yudens) are fine. Maybe it was just that particular disk then. Thanks.