In many cases, new or second operating systems are installed onto a secondary partition in which a boot manager can decide which partition to boot off of. All too often, there is either too little or absolutely no space left on a hard drive in order to accomplish dual-booting.
In other cases, multiple partitions can also serve as a place to store backups. With software designed to resize partitions, users are given the option to resize their current Windows partition in order to allow space for a secondary operating system (such as Linux). The partition managers are those which are fully capable of resizing a currently in-use partition.
Easily manage, delete and split up partitions on a physical hard drive with other options available such as merging, backup and recovery.
Partition Assistant Home is software which can resize Windows partitions.
Free partition management utility that can resize partitions, erase partitions and has HDD tools for keeping track of drive errors.
Partition Wizard Full Version is software which can resize Windows partitions.
FREE and ALL-IN-ONE magic partition solution and disk management utility.
EaseUS Partition Master Home Edition is software which can resize Windows partitions.
Resize, copy, move hard disk partitions, now included in Acronis Disk Director.
Acronis Partition Expert is software which can resize Windows partitions.