Hi Euni,
Definition of explorer.exe:
"explorer.exe is the Windows Program Manager or Windows Explorer. It manages the Windows Graphical Shell including the Start menu, taskbar, desktop, and File Manager. By removing this process the graphical interface for Windows will disappear."
As a file manager the process really shouldn't be using any data itself. That process however is a favorite target of virus and malware writers.
I have to agree with Corrosive in suspecting a virus or malware infection.
I suggest for starters you read this:
https://malwaretips.com/blogs/remove-explorer-exe-virus/
I also suggest that you download, install, update and scan your computer with the free version of Malwarebytes:
Can you post a screenshot the Glasswire output showing the IP location(s) where explorer.exe is going?
Use this as a guide:
Usage Tab
Apps Button
In the left column click on the process (I highlighted Host Processes as I had no explorer.exe)
In the center window click on the top item, That will display where the process was connecting to.
Hi Euni,
"Now since I have windows 7, forgot how to do and post snapshot, help...."
Instructions on using the Win7 Snipping Tool can be found here:
http://www.howtogeek.com/207754/how-to-use-the-snipping-tool-in-windows-to-take-screenshots/
To then post the screenshot here in the Community first click the highlighted "camera" icon and then use the highlighted "select a file ...." to select the Snip you wish to post:
Use the opening window to navigate to where you have stored the screenshot on your computer"
"Gwalk, I read the instructions above, can I print this out?"
Yes
"Are these programs free?"
Yes
As long as it is no longer appearing there is a really good chance that Malwarebyes took care of the issue and things only need to be closely monitored.
There is the free version of Malwarebytes and I run it myself. It is "reactive", that is to say an after-the-fact scanner. Only the paid version runs as a "resident".
As stated, I use the free version and once per week I will manually open the program, update it and do a scan.
I do a manual scan with my anti-virus program weekly also.