Schedule Windows housekeeping?

First things first. We need your system specs. Use this tutorial by Brink to help you do just that.

System Info - See Your System Specs

The way I do my house cleaning and I do it often is do it manually along with manual updates of everything. No Auto or scheduling anything.

Doing it this way means I get done what I want done when I want it done so it doesn't interfere with my work. If done often it really doesn't take long because you are never far behind the cleanups and updates.

You job on the specs is very good but a few other things could be added that might be needed later.

Look at my specs and how they are filled out will give you a idea.

The reason this spec thing is done is so other can help better if you ever need help.
The more information others can quickly see when need be is better.

Check msconfig Startup and Non Microsoft Services and see if you have programs auto checking for updates. Like Adobe, Google, Chrome ect. If you find them uncheck them. You will have to check for updates your self.

I use this program on demand to check if things need updated. It only checks when I tell it to, therefore on demand.

Download FileHippo App Manager 1.47 - FileHippo.com

Let us take a look at some things.
Please post these pictures of your system.
The reason is you have 3 gigs of ram, which is okay but only so much can be done with 3 gigs of ram at one time.

Could you put in your specs exactly what motherboard you are using. Ask if you need help to do so.

Use this tutorial by Brink to post snap shots.

Screenshots and Files - Upload and Post in Seven Forums

Did you look at my (My System Specs) an notice I listed the power supply and security system I use.

Remember that the more information in your (My System Specs) the less question other members have to ask when trying to help you.
Some anti virus programs can slow your computer down a bunch.
Their are many things that can cause your problem or a combination of things and that is why I ask for so much information.

Your system is long in the tooth but many things can be done to help it along in it's old age. The Intel 920 was a great cpu in it's day.

Way way to many Startups and Services.

Look at mine in the post again. I got 3 checked in Startup and 1 in non Microsoft Services.

Let me explain.
All those you have checked have no need to start at boot.
Just your security programs need to be checked.
Programs that don't start with the boot still we work as normal they just won't be running in the background wasting your computer resources when you are not using those programs.

Now we know for sure where part of your problem is.

Startup hell.