Need Help looking for a good antivirus software

Hi I Am new to this. iam looking for a good antivirus software i have looked at kaspersky, avg, norton but norton is to much on System Requirements and look at mcafee as well. can someone tell me if avast has advanced Heuristics and does it scan for Malware and spyware as well if i install avast what firewall can i use. and if it does not scan for Malware and spyware anyone no of a good spyware and Malware scanner i have to computers that iam look and antivirus for 8)

one Iam running windows xp pro 2G memory and AMD 2200-1mb Dual Core Proc Opt and harddrive is a Seagate 750GB 7200RPM ATA100 16MB Cache
the over computer is running Windows Vista Home Premium Edition 2G memory and AMD 2200-1mb Dual Core Proc Opt and harddrive is a Seagate 750GB 7200RPM ATA100 16MB Cache Thanks

avast uses less resources than Norton.

Only for mail. avast uses generic signatures to detect ‘unknown’ malware.

It has a good spyware detection, but it is a antivirus not an antispyware.

Any. I suggest Comodo or PCTools, both free.

AVGantispyware or a-squared. Other users use SUPERantispyware.

Welcome to avast forums.

The combination avast!, Comodo Firewall and AVG Antispyware (paid version) work just fine here.

I used Norton before avast and I’ve been happier since then. Avast works better than Norton with less resources.