I may have an answer. I don't know if this answer will apply, but I've seen other threads on-line similar to this one. My problems with loss of memory started after I turned 50. Oh wait, wrong issue - seriously now: my PC memory leaks started when IE10 was automatically installed; I went back to IE9 and the issue disappeared. Then IE11 was installed and the memory eating dllhost com surrogate reappeared. Using Process Explorer I'd see DLLHost launch a COM Surrogate process which would last a few seconds; close with another launch right away. This kept happening until the system ran out of RAM; I'd reboot and after 2 or 3 days the problem would begin again.
I'd suggest looking into using Process Explorer vice the native Windows Task Manager. Far greater detail and insight as to what processes are launching and what is eating your memory. IF it turns out your issue is tied to the dllhost.exe Com surrogate bug (that is well known now) I have a solution. It's worked on both Windows 7 and Windows 8.1
I looked around many boards and searched, never finding a satisfactory resolution. At the end of the day - for me - the issue was IE10 and IE11 does not play well with add-ons. I reset IE11 to it's base state, rebooted the computer and 10 days later no errant dllhost COM Surrogates eating memory.