Hello YoKenny!
@Asker: first I must say, yes, other friends are right, pagefile.sys is not possible to scan, but it's like your memory, if it's detected it must be because a malware is running in your computer and it's loaded to memory...
you can see my Laptop configuration in my signature, I use Outpost Firewall Pro 2009, but I've not install the Antispyware and Webcontent control that come with that
go with avast!, I would promise you it would not slow down your computer and protect you against any virus and almost all spyware and other kind of malware, I've played with many many AV and other security software. you would not need any other real-time protection beside avast! AV, just you need 1-2 on demand scanner (they would not slow down your computer because they don't run in background) like Malwarebytes' Antimalware or SUPERAntiSpyware. avast! has Free edition which would protect you with same Virus definition Professional Edition has, Malwarebytes' Antimalware and SPUERAntiSpyware are Free too.
http://www.avast.com/
http://www.malwarebytes.org/mbam.php
http://www.superantispyware.com/