slow performance

Well, now that I got my computer back running, it is slow. It was slow from the start and then I got those problems with it.
But anyway I have windows 7 and use firefox browser and yahoo mail. My computer is slow. When I go to open a mail it has the word "loading" on the page and that stupid little blue thing just goes around and around. That "loading" I didn't have until a few months ago. Is there steps to take to speed this thing up and give it a good cleaning? I am a novice, so take that in mind please. Thanks.

Please fill out your system specs so we know what we are dealing with. Hard to tell when we don't know what you have.

What are system specs and where do I go to find them?

Specs means specifications. You have already filled in your OS. You access from the user control panel. Look in the left hand margin.

We need to know what CPU and how much RAM in particular.

My computer must be different, I have nothing o the left hand margin. I do know I have 3 GB of ram, but I don't know what CPU

well, I found it, but there was a whole list of specs - what exactly do you need?

CPU and RAM in particular. We already know your OS if your system spec is correct.

I have an intel core 2.0 duo cpu E7400 @ 2.80 9hz 2795 memory
3 gb of ram. Is this what you need. There is a whole list of stuff, just took a chance on what you needed. Thanks.