How to avoid spyware

My pc is quite old and I have been told that having anti spyware installed on it will slow it down by at least 25%. I am thinking what is the lesser of two evils! No anti spyware or invasion by spyware! As I am fairly new to computers I am at the moment being fairly cautious about downloading things. Advice much appreciated. I am on XP proffesional.I am so puzzled about this problem.I have no ideas so i ask some one for help.I am so lucy and one of my friend tell me SpyNoMore is a good program for detect and clean spyware and I can find it byhttp://www.converter123.com. On this web site I find so many useful softwares.Truely,SpyNoMore is so valuable for using.Finally I had solved the problems of my computer.If you have problem with the way to use the software,I can show you the way as following: 1.You can free download it from http://www.regnow.com/softsell/visitor.cgi?affiliate=512860&action=site&vendor=13095&ref=http://www.converter123.com/Other-Software/SpyNoMore.zip and you will find the file named SpyNoMore.zip 2.Run the file,Click snm-2.67_swpl.exe to following installation. 3.Finished the installation,you will get the interface of the software.You will find 7 menu og the software,They are:Startscan,Removespyware,Rollback,Costom Fix,Active Protection,Setting,Updates. 4.If you want to clean the Spyware,You can click Removespyware,Of course This operation need you scan your computer first. so you must click StartScan before,if you click Star Scan there is a window will show you one is Smart Scan and another is Full system Scan.I suggest you use Full system scan if your computer is not safe enough.Then choose scan now.There is a dialog box show you the result of the scaning.You can choose the Spyware by check the result. 5.Click Remove Spyware then the software will help you to clean the Spyware which were found on your computer. 6.you can click setting to set the scan calendar. 7.You can click Updates to update the software. Not only these function but also SpyNoMore can help you to avoid malware,virus or more.Once upon a time I had lost my password og World of Warcraft but SpyNoMore show me a warning,I easily get it back. Symptoms that your PC is Infected: ?You receive frequent popup advertisements ?Your homepage taken over by an unfamiliar website ?Your computer becomes increasingly sluggish ?A new toolbar is added to your Internet Explorer browser ?Your browser is slow to open and / or requested pages are slow to load ?Your searches are redirected to unfamiliar websites ?Your system becomes unstable or you encounter frequent computer errors ?Your computer connects itself to the internet or sends email messages without your permission ?You see unknown or suspicious processes in the list of running tasks ?Unknown software is installed on your computer without your permission ?Unknown users connect to your computer remotely without your permission ?You experience a surge in unsolicited emails arriving at your inbox If you find one of these,please try to use SpyNomore. More information : http://www.converter123.com/