In addition to the submission by @FuzzyToothpaste, see my answer to a similar question:
"This computer currently has no detected operating systems."- Ubuntu 14.04 install Windows 8.1
which outlines the steps involved to dual-booting with Windows 8.1, with a link to detailed instructions.
Clarification: did you erase the Windows partition during install, or is it simply inaccessible?
If it was removed,as you have a saved back-up image, this link may also prove useful:
It discusses the steps involved with restoring Windows 8.1 from a back-up image using the Recovery Environment.
This link, in response to OP comment, is a breakdown of the steps involved to boot Windows 8.1 using your System Backup Image. Three options are offered:
1) restore using the Recovery Control Panel(this is the recommended option)
2) restore using pre-installed recovery options
3) restore using Windows installation disc or system repair disc
Note:Available options will differ based on your hardware. These are general instructions, refer to your hardware manual for specifics on terminology of these options, and HotKey commands to access BIOS, if necessary.
Related: see this link:
The above lists the Setup Utility directions specific to your hardware(or as close as I could find) for restoring Windows from Installation Media. The below listed method(from link) is the closest to your intended use.
Boot to Recovery Environment with the installation media:
Please follow the steps given below. Insert the Windows 8 installation DVD in the DVD ROM and restart your computer.
a) After you boot your computer using Windows DVD or System Repair Disc, a black screen appears with gray text "Press any key to boot from CD or DVD". Press any key.
b) Select the correct time and Keyboard type.
c) Click Repair your computer in the lower left corner.
d) Select Troubleshoot from Choose an option screen.
e) Click Advanced options in Troubleshoot screen.
f) Click Automatic Repair from Advanced Options screen.
g) Next, choose the operating system.
h) Windows 8 will then look for problems on hard drive(s) and verify that all required files are intact.
Should any of the above resolve the issue, in the future, see
this handy guide for dual-booting WIndows 8 and Ubuntu in 10 easy steps