1.放心大胆地安装吧,系统乱了,可以system restore到安装前
http://windows.microsoft.com/en-us/windows7/Create-a-restore-point
2.实在不放心,那就到Start-〉All Programs ->Maintenance -->Backup & Restore,可以做各种花样的备份
http://windows.microsoft.com/en-CA/windows7/products/features/backup-and-restore