Can Windows 7 on Bootcamp cause problems? If I install Windows 7 on my Macbook Pro using Bootcamp, can Windows cause problems on the OS X partition? Can it overwrite OS X system files or corrupt my data? My main concern is that I need to use Windows 7 for some school and work related things throughout the year, but I want to keep OS X clean and healthy throughout the process.
Bootcamp will create a separate partition for the Windows installation. This NTFS-formatted Windows partition is completely separate from the OS X partition.

Moreover, you can always delete the Windows partition and return your HDD to its original state.

In other words, Bootcamp should be pretty safe and won't touch your Mac installation nor should it touch your files on the Mac partition.