I installed the backup software that came with My World Book Edition II on my new Windows 7 64 Bit operatiing system. The computer would take 10 to 20 minutes to shut down, would not respond to many programs, would not accept USB devices. After much analysis, the problem appears to be that the CONTINUOUS back up software grabs files and if it happens to grab files that are vital to normal operations it can crash your computer. After 3 days of crashing I finally removed all traces of WD’s backup software and the computer works fine. If anyone else experienced the same problem please post.