With five different operating systems running here on far too many computers, I see it all the time.
I'm That Guy. I'll say it this way: Yes, I can fix your computer, but I won't do it for free. I'm done with that free stuff.
On the other hand, I hear this too many times. Someone went out and got a new computer because it's too slow.
The "new-to-me" computer I am using to write this on is a 5 year old. It's running Windows 8.1 and it's running it quite well. The one I do most of my professional work on is a 7 year old beast running Linux or/and Windows 7. My file server is a 12 year old laptop running Windows 7. That runs well too. Laptops consume less power and space and do the same job as that beast of a desktop I used to love to build back in the day.
You say "Sure, but you know how to make it go faster".
Yep. It's simple. I don't allow software foisted on me. Crapware. Foistware.
I was giving someone an old computer once who was staying for a few days. Recently. The day after he got the computer he had two pieces of Foistware already installed.
He got it when he went to install Skype. I guess he wanted to be spied on, but he also wanted to talk to people in his family that was scattered all over the globe. So I told him to go find the download and install.
Wrong person to do that to. He went to a "Partnered Download Site" I was told. Red lights and fire engine sirens went off in my head. He ended up with a toolbar on the browser and a redirected home page. I growled at him, fixed it, then sent him on his way.
Two very simple rules to avoid this kind of garbage.
First, make certain you are going to the software vendor's approved site for downloads. That means it's going to require you, and not someone else, to do the research for you. Skype is pretty simple, it's a Microsoft product, so go to Microsoft to find it. That takes care of the honest software producers.
Second, always, and I do mean ALWAYS, when you are installing the software use the Advanced install. When you are installing, actually read the page that is presented. Don't simply click "Next". That's how you get the crap installed in the first place. That helps to take care of most of the dishonest software producers.
You don't ever need a toolbar on your browser. If you get one, remove it through your control panel's "Programs and Features" list of programs. There are way too many programs to list here, but you will then be able to remove the "feature" by double clicking on the name of the program. Other more evil toolbars are actually more like a virus, and you will need to do research on how to get rid of them.
If it truly is a virus, it gets much more complex, but here's one way of fixing all that garbage.
That is the same place you can go to when you find yourself with a program needs to be removed, such as anything is riding along and doing "useful" things like presenting you with ads or anything by McAfee.
Why do I mention McAfee specifically? Adobe Flash. If you aren't careful, when you do a security update for them, you will end up with the helpfully named "McAfee Security Scan Plus".
You don't need it. More "Foistware". All this "Foistware" slows you down. You can get rid of it, or you could get a new PC and start over. One requires less time than the other. Since many computer stores that you can actually visit have a nasty habit of trying to upsell you to a more expensive model, you should try to delay that particular task as long as possible.
Basically be careful and watch what you're doing. It is, after all, your computer. Just because a particular NEW! and shiny piece of software is "suggested" to you by something you actually want, doesn't mean that you need the blasted thing.
In return, you may be able to skip a new computer next year.
How great would that be? An extra couple hundred bucks in your pocket? Or Pounds, or Euro?
You'll thank me later.