Nuendo 5.5 stopped working


My hard drive was becoming very full, so I exported lots of movie material and pics to external hard drives, no music files or project files were moved. Had to defrag hard drive after that. Now Nuendo 5.5 won’t start, I get the message “Nuendo 5 has stopped working” and that’s it. I have removed it and re-installed, but it’s the same message. I run a 64-bit version on PC and never had any issues whatsoever… Any suggestions?

Best regards,