well 1st: stop all programs and check the taskmanager
as i did see in your pic world of tanks for example
Close all Browsers (check at tasklist if closed) cause browsergames often make this trouble
the svchost can refer to a tiny Little program which only uses 1 or 2 MB but opens a secondary huge process,
if all programs / unnecessary processes closed wait a Little time - watching the taskmanager may be 10 minutes.
check autostart and scheduled Tasks what they do
the Memory will reduce when you kill all Tasks shown at the taskmanager where owner is "Leam" - they wont deinstall - they just are killed -
when killing a process something to your Memory use will happen - check which one you killed, reduces Memory use - then you found the reason / program causing trouble.