If you are not willing to pay for it, then use free version. It provides the same level of protection as payable one. It just has less features and extras that might enhance protection but are generally not needed by everyone.

Since you’re using WinXP (as i can see from the windows on those pictures), why are you sticking to an outdated version that is slower and has a worse protection than avast! 6 ? I’d understand if you were still on Win9x where avast! 6 doesn’t work anymore, but insisiting on avast! 4.8 on WInXP just doens’t make any sense at all. The whole point of ANY antivirus or security program is to be as up to date as possible. Only this way you can always be ready against latest malware. Which you just can’t be with avast! 4.8 anymore.

avast! 4.8 is using an outdated engine, its emulator is much more basic, it doesn’t have proper heuristics, doesn’t provide Script Shield, it doesn’t have Behavior Shield, it doesn’t have AutoSandbox and also scanned files are not cached which significantly increases performance.
You get all this in avast! 6. For free!

I’s like having a choice of a free Ferrari 458 Italia and a free Zastava Yugo. And you’d pick Yugo and insist on it to the death. WHY!? Take the Ferrari, take the avast! 6…