Help with partitioning for dual boot with windows 10?

Often you have two partitions you can backup & delete, both recovery partitions, so you need to make those recoveries first.
One is usually a vendor recovery, which can restore system to as purchased. Often really on useful if selling system. Some may kept your data, but better to do your own full backup first.
One is often a vendor tools partition. Those files often are small so easily backed up and many vendors let you download those again if needed.

The vendor recovery DVDs are just an image of your drive as purchased. If you have housecleaned a lot of cruft normally included, run many updates with many reboots, and added software you may want a full back up.
Backup windows before install - post by Mark Phelps
http://ubuntuforums.org/showthread.p...0#post12611710
http://www.macrium.com/reflectfree.asp
Another suggestion by srs5694
http://www.runtime.org/driveimage-xml.htm
Microsoft Windows 8.1 reinstall/refresh
http://windows.microsoft.com/en-us/w...-refresh-media

With my Windows 8 system, I made Dell recovery, Windows recovery and a full backup with Macrium. Multiple DVDs & a couple of flash drives, one was 8GB and the full backup used about 26GB on a 32GB flash drive. And I had not installed or added any of my own data.

My laptop already has 4 primary partitions: how can I install Ubuntu?
http://askubuntu.com/questions/14982...install-ubuntu
Good advice on how to handle all four primary partitions used. - srs5694
http://ubuntuforums.org/showthread.php?t=1686440
Be sure to create recovery DVD(s) first. And a Windows repair CD.
HP tools partition discussion - similar for other vendor utility partitions:
http://h30434.www3.hp.com/t5/Noteboo...on/td-p/228360
For a complete blow-by-blow on dealing with HP's four partitions, see Full Circle Magazine, issue 41, page 36. - gordintoronto
http://fullcirclemagazine.org/