Could this be my hard drive problem?

Basically the problem I'm currently experiencing is that running too many clients of one game gives me ton of lag, but the lag is weird, because it's only when I press down on keys and stuff, for example when I press up a button to open my inventory, I would freeze, but when I move around the world by clicking on the ground, it would run smoothly.

In the resource monitor this is what happens when I hold down a button for approximately 5 seconds and release it.
http://postimage.org/image/i3a10knxx/

So I was wondering if this was my hard drive causing the problem, everything else on my computer is great, in the windows experience index rating thing everything has either a 7.8 or a 7.9 out of 7.9. while my hard drive is a 5.9.


Additional information: I can generate this lag by just holding down any button on my desktop when I'm running multiple clients of games, and move/click my mouse when doing so, a series of beeps will come up, and will beep according to my choppy mouse movements in the meantime, I'm almost certain this is what is causing the lag but cannot find out what it is even after hours of researching. (It's not stick keys, toggle keys, filter keys, etc.)

Help will be much appreciated.