i7-3770 with 8GB of RAM is lagging

This computer is about 1 year old, and I thought it should be pretty potent, but lately it's lagging.

It's an i7, I have 8GB of RAM, a WD blue caviar 1TB hard drive and an AMD Radeon 7800 series graphic card.

I'm attaching the diagnostics from the SF Diagnostics tool.

A few things I've noticed:
- Memory is always at 60%-80%. Chrome being the main consumer.
- The hard drive has weird spikes in the Resource Monitor. In the following example, it was all nice and low until I decided to close a Notepad file (5 lines, didn't even save!). The numbers in the hard drive graphs bother me a little... is it normal to have a max number of 0.01 in the queue graph, and of 10MB in the disk graph? (graphs attached)

Could you help me out? Is it just a RAM problem? If I can, I'd like to avoid buying another 8GB, unless it's the absolute certain cause of the issue.

(As a sidenote: I am a web developer. I normally have Sublime Text, Prepros, Sourcetree and one Adobe program open, apart from Chrome, to test everything out and look for language documentation. It did not use to be a problem)

I added some of the specs, and I'm adding the resource and memory screenshots. Right now the computer is working without any lags, but hopefully it gives some insight anyway.

Twice as many as most sounds bad

Here's the info you requested:
Running processes



Chrome, Explorer and Spotify are half of those processes.

MSconfig startup:




The disabled processes are newly disabled, I haven't actually restarted the computer yet.