|Your computer are infected with virus and spyware.|
you should update anti virus program and scan whole computer.
You can also download and install Malwarebytes and scan your computer in Safe Mode.
After scanning you can change the extension of file.
Open My computer > Tools > folder options > view tab >
select "show hidden files and folders.
Remove the tick mark from " Hide extensions for known files types".
And also remove tick mark from " Hide protected operating system files.
Click on Apply and the OK.
Select any jpeg file (means now, exe file). Example, abc.exe
Right click Rename > change the file name or extension from ".exe" to . "jpeg".
abc.exe > rename the file > abc.jpeg
Try to reboot the computer and check