Hi,
You might be facing this issue due to some corrupted boot files. I suggest you to try the following steps and check if it helps.
If you don’t have a Windows 8.1 DVD, you can refer to the article mentioned below to know how to create a bootable USB\DVD for Windows 8.1.
How to create installation media for a PC refresh or reset
http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media
I suggest you to change the first boot priority to DVD\USB if you are not able to get the boot menu when you insert a DVD\USB.
Let’s try these steps to restore Windows 8.1 from a system image or recovery disk.
To restore using a Windows installation disc or a system repair disc:
1. Insert the installation disc or system repair disc.
2. Restart your computer using the computer's power button.
3. If prompted, press any key to start the computer from the installation disc or
system repair disc.
If your computer is not configured to start from a CD or DVD, check the information that came with your computer. You might need to change your computer's BIOS settings. For information about which settings to change, check your computer manufacturer's website. For more information about BIOS, see BIOS: frequently asked questions.
Note: Modifying BIOS/complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.
4. Choose your language settings, and then click Next.
5. Click Repair your computer.
Note: This step only applies if you are using a Windows installation disc.
6. Select a recovery option, and then click Next
To restore using the Recovery Control Panel (recommended):
If your computer is working and you can access Control Panel, or if you want to restore your system image backup onto a different computer, follow these steps:
a. Open Recovery by pressing Windows Key + C, and typing Control Panel. In the search box, type recovery, and then click Recovery.
b. Click Advanced recovery methods.
c. Click Use a system image you created earlier to recover your computer, and then follow the steps.
You may also contact the System Manufacturer in case if you are using the manufacturer’s utility to restore the system image.
Do let us know about the results. We will be happy to assist you further.