Once Ubuntu / Linux Mint is installed along side with Windows and then it is removed, it may happen that booting into Windows after that  may no longer be possible.
The boot process may end with a grub rescue prompt and no further activity can take place. To fix this, all we need to do is once again make Windows repair the Master Boot Record (MBR).
For this :
1. Use the Windows install disc or setup, then choose the language and input method, then select “Next”.
2. Select “Repair your computer”.
3. Choose the operating system to be repaired and select “Next”.
4. In the System Recovery Options dialog box, select “Command Prompt”.
Once the prompt is launched, enter the following two commands one by one :
The notification that should be displayed after entering these commands would be something like “This operation has completed successfully”.
Now restart the PC, the grub rescue prompt should no longer be present after the boot and Windows will boot up normally.
Cheers.