Saved OS and programs

I am looking to switch to a Mac and was looking at the ways of install Parallels Desktop.

I am going to install Windows 7 via Boot Camp and use Parallels Desktop to run my Windows programs on the Mac.

Q1 - Will Parallels Desktop read the OS and have all my already installed programs installed by switching OSes on startup or do I have to install the programs through Parallels Desktop?

Q2 - Do my preferences save after I am finished with Parallels Desktop? For example if I change the taskbar to the top of the screen will it save the preference for the next run? Also, if I install a program, will I have to reinstall it on next run of Parallels Desktop? And finally, can I save a file e.g. a Word .doc document onto the Boot Camp partition?

Q3 - If I switch to run windows natively at startup, will I still be able to see all the changes made in Parallels Desktop?