Hi Harshvardhan
atikmpag.sys is the device driver on your ATI/AMD graphics card . . .
Open Device Manager (accessible by right clicking your Start Button)
Expand the Display Adapters Section
Right click your video card and choose Properties
On the Driver Tab, choose 'Roll back Driver'
Restart your PC once done . . .
If that option is grayed out or does not resolve the issue, go to the support page for your device on the manufacturers website, then download and install the video driver they recommend, it may well be an older version to the one you are currently running
If your system still crashes, check to see if your PC is producing any minidump files, I will check those to see if they provide any insight into a potential cause of the system crashes . . .
Open Windows File Explorer
Navigate to C:\Windows\Minidump
Copy any minidump files onto your Desktop, then zip those up
Upload the zip file to the Cloud (OneDrive, DropBox . . . etc.), then choose to share those and get a share link
Then post the link here to the zip file, so we can take a look for you . . .