Hard Drive LED light remains on all the time

The red hard drive LED light on the front of my computer remains flashing all the time even when no apps are open.  It appears some activity is taking place in the background.  Is this normal.  When I view Local Services, there are many items listed that are running but which ones do I stop from running?  All responses would be appreciated.  Thanks.

Some possible culprits: Windows  Update, Search Indexer and Windows Search, Anti-virus.

Aslo an infected computer often has a lot of drive activity. Run your AV scans and Malware Bytes Anti Malware Free, see what shows.

Thanks for the response. I did run both Malwarebytes and Windows Defender but no threats were detected. Another issue has also arisen.  I find that now Windows Live Mail takes ages to start.  It takes almost ten minutes before it starts but thereafter it works fine.  I have even uninstalled and re-installed Windows Live Mail but in vain.  Perhaps this is related to the constant hard drive activity?  Alternatively, could it be malware that cannot be detected by anti-virus programs?   

do a clean boot and see if it still happens. :- https://support.microsoft.com/en-us/kb/929135

Thanks.  I have done a clean boot twice but to no avail.  The red LED light remains on and flashing all the time.  There must be something happening in the background and, as regards Windows Live Mail, it still take ages to start but not so with other email clients (Thunderbird and Opera Mail). 

Is there a way to re-install or repair Windows without affecting any of my files and email messages.  I hesitate to do a Refresh and previously the process deleted all my email messages and recovery was not possible.  When I tried to import the messages back from the Windows.old folder, only the headings were recovered but not the messages.    

What ever course you chose, backup first. Ideally do an image backup to an external hard drive using Macrium Reflect Free.

That way no matter what happens you can recover.

I don't understand why, in the hostile world our computers work in, people (not just you) don't do regular backups already.

You can get a 1TB External USB 3.0 hard drive for $60 and Macrium is free.

Look up how to migrate WLM and do that before you do anything else, that way you won't lose E-mail.