Since you have no access to the Advanced Boot Options Menu, let's give the following a try...
Use HitmanPro.Kickstart to access your computer, scan it for malware, and remove this infection. The program targets this ransomware.
Also, you may want to print these instructions, so they are available to follow.
Now, load a USB pen drive with HitmanPro.Kickstart as follows...
Note: the contents of the USB flash drive are erased during this process!
Use a clean (non-infected) computer, and download:
HitmanPro.Kickstart - Anti ransomware, politievirus, bundestrojaner, Reveton, BKA, GVU - SurfRight
Under Download (on the right) select the program applicable to the system: 64-bit, or 32-bit?
When HitmanPro opens, click the KickStart icon at the bottom of the screen.
>> Plug in the USB pen drive.
When the USB pen drive is detected, a selection screen is presented.
Select the USB pen drive from the choices, and press: Install Kickstart
A warning that all contents of the selected pen drive will erase is presented.
As the HitmanPro.Kickstart files are loaded, a progress indicator is shown on the screen.
Once the process is completed a screen is presented with the contents of HitmanPro.Kickstart
Remove the USB flash drive from the clean computer and press: Close
Now, with the ransomed computer shut down, plug the USB flash drive into a USB port, and turn on the power.
When the computer starts, press the key that brings up the Boot Menu. (On some machines its F12, F10, or F1, F2)
From there, select to boot from the USB drive. (It may say 'Removable Drive' in the options.)
Info: How to Remove Ransomware - Select Real Security
Once you select the USB flash drive to boot from, press: Enter
A Kickstart prompt with USB boot options appears.
Select: 1 (Bypass the Master Boot Record (Default))
The system continues to boot from the hard drive and starts Windows.
If you get a message stating that Windows failed to start, etc., just select: Start Windows Normally
When Windows boots, you either get a logon screen, or the Desktop is started.
If you see a logon screen with your User name, logon with it.
In the next prompt that appears, to start the program without installing to the local hard disk, select the option to do a: One-time scan to check the computer.
To start scanning for malware press: Next
If malware is detected, the program shows what malware is present on the system in the Scan Results window.
Select Next to quarantine the malware into a secure storage where it can no longer start.
At the next screen, activate the 30-day free license.
After successful activation (30 days), press: Next
A screen indicating that the malware was successfully disabled or removed is presented.
To obtain a report of the scan results, press: Save log
>> Save the Notepad log to the Desktop, if possible, or to the pen drive.
(It has a name such as: HitmanPro_xxxxxxxx_xxxx)
Restart the computer.
If able to save it, please provide the HitmanPro report in your reply.