Honestly, sometimes you get what you pay for, but there are plenty of very good, free applications that are completely legit and can help you do a lot to fix up your computer.
Here's a list of a few programs I would HIGHLY suggest:
CCleaner
- CCleaner is a great tool for generally cleaning up your system, getting rid of temporary files and other such things that are just taking up space on your computer. It can also scour through your registry and find entries that you can safely just get rid of, which can help with performance as well.
CCleaner - Home
Spybot S&D
- Spybot S&D is one of a number of good, free anti-spyware, anti-malware programs. It works well, and should take care of most problems you run into. Granted, if you were to buy software like SpySweeper, you can probably benefit from more resources dedicated to making software which finds and gets rid of more spyware and such, however there's no harm in at least trying this software first, considering it works great and is free.
The home of Spybot-S&D!
Windows Defender
- If you're running windows XP, it's worth your while to download Windows Defender, as it's free, and it's just more anti-spyware, anti-malware protection. Granted, it has scans automatically scheduled for FAR too often, but you can change that pretty easily. Doesn't hurt to have it.
Windows Defender: Home Page
One thing I must say, is that the free anti-virus programs are fine, and you can look up ratings for how each does, performance-wise and protection-wise. The important thing to remember is, though,
don't have more than one anti-virus program running active protection at the same time. That can really cause some annoying problems, aside from bringing your computer to it's knees in terms of speed. For anti-spyware, though, it's more worthwhile to have multiple programs installed, as long as you don't have them actively running at the same time, since that'll hurt your computer performance as well. But individually running anti-spyware scans with different programs is very beneficial.
Anyways, sorry for the long post, but there's what I have to say about that!