hi,I have just installed avast! 4 Home Edition and I wonder if this also protects against spyware. Should I disable the Windows XP SP2 Firewall? Can I do without Microsoft antispyware? Thank you 
avast is by specialisation an antivirus, it does however detect some aadware/spyware generally the more serious spyware and adware, so I would say you still require a specialist anti-spyware/adware tool and MS antispy fits the bill.
Some others to consider are:
avast! isn’t a firewall, you need a firewall and MS XP firewall is better than none but it only provider inbound protection and no outbound protection. Zone Alarm free is suitable for the novice firewall user with a reasonably friendly interface.
You can also try the new great free version of Spyware Doctor
:-*thank you for instant reply!!! This is great…
Happy to help welcome to the forums.