If you do not know enough about the Windows XP op system to know how to display hidden files and folders and protected system files, or how to dump temp Internet folders, do yourself a great favor and stay out of them or you will find yourself trying to reinstall XP soon afterwards, if you even have a way to do so which not everyone has.
I also suggest that you do not use any "registry cleaner" or anything else that modifies of changes the registry unless you are fully literate in the registry and know how to repair what may be a registry change that has a deleterious effect.
The better way is to tell us what problems you are experiencing and allow us to assist you.
You also say,
sometimes I get infected with viruses or spyware
like that is something normal. It isn't, and there are ways to protect your computer from becoming infected in the first place.
What anti-virus program do you have running on your computer and how often are its definitions updated? Do they update at least on a daily basis automatically?
What anti-malware aps do you have resident and running? How often are they updated? How often do you scan with them and are any running in realtime like Spybot's Teatimer or Windows Defender?