What action makes RAM on your computer disappear?

Use Windows Task Manager & Resource Monitor. The easiest way to free up RAM in use is to open Windows Task Manager. Navigate to the Processes tab and then sort the list of open programs by memory. This will reveal any process that's consuming an unusually large volume of RAM.

Solution:

Due to the following ways it happen

1) Many startup program

2) Hard drive is failing

3) Hard drive is 95% full

4) Browser has to man ads-ons.

5) Running of to many programs

6) To many browser tabs are open

7) Rogue programs are hogging all the process

8) Having virus. Etc