Windows 7 64bit, Memory usage rises/computer freezes over time.

I've noticed over maybe the last few days..my computer would randomly freeze/slow down, yet cpu usage and memory in use is low.

It says all of it is cached right now..i don't know if that's normal for Windows 7 or what.
It's not freezing right now but it eventually will, yesterday i got the low memory warning and my computer completely froze up.

I really dunno what to do as my memory doesn't seem bad, neither does the hardware. I only got this computer a little over a month ago and it's been working great, infact it still does aside from these freezes over the last few days.

EDIT:
I'll post another screenshot of when it actually happens to see if there's a difference.
But i noticed my svchost file is at around 331mb of ram..i have 16gb so that shouldn't be the issue though. >.<

Have you run any tests on the hard drive or on the RAM?

Have you run sfc /scannow from a command prompt?

Are you virus and malware free?

What anti-virus do you use?

Will this eventually happen if you just start the PC and walk away from it, with no applications opened?

I haven't run any tests yet on HDD or RAM, currently doing virus scan/sfc-scannow
What should i use to test them?

I use Norton (Internet Security 2012)

It hasn't happened when i walk away from it either.

I'm pretty sure something ends up stealing ALL of my memory. But it doesn't show up on Task Manager..

Use the drive manufacturer's utility to test the drive.

Use memtest86+ to test memory. Let it run for 6 or 8 passes. You have a lot of RAM, so that may take overnight or longer.

You could also start pulling random RAM sticks and see if it persists with the remaining sticks. But I'd run memtest86+ regardless.

I'd try to find out if it happened with Norton disabled.

If it doesn't happen when abandoned after a startup, it presumably has something to do with something you later start.

I'd run a malware scan from someone like Malwarebytes.