When a computers disk/cpu usage is supposedly 1-5%, what can cause it to be unresponsive?
 

That is, not being able to change windows(even with alt tab), simple dialog boxes taking 3-4 seconds to appear, etc

hard drive failing.

I know what you're talking about, but, this has happened on every computer I have ever owned from time to time ... new or old .. there are times when it shows 0% or 1% cpu and disk usage and seems to be slowing to a crawl - then blam - everything is processed/happens all at once, it seems like

Perhaps when it happens, it's just so busy it cannot report actual usage numbers .. but I have tried giving, for example, task manager the highest priority and it still happens

problem is between the keyboard and chair.

Upgrade your RAM

You have 2 choices

1 - Upgrade from Windows 95

2 - Get a Mac

I suggest option 2.

Well I have 6gb in the system right now and it happened when I was only supposedly using 1gb

networking issue?

It must be windows having a problem addressing blocks of memory .. it just has to be .. right?

it may be full of poo... (it happens) Have you sniffed it???