do I need other soft ware to detect spy,mal, adware ?

I am not computer literate. I have an old millennium system and use yahoo mail and IE. My computer is getting slower and slower.
I have used AVAST home for years with little problems.
My geek buddies tell me that Avast alone is not enough to stop the new infections.

What say You?

Absolutely, Superantispyware, compatable with windows 98 onwards, and MAlwarebytes Antimalware Windows 2000 onwards.

http://filehippo.com/download_malwarebytes_anti_malware/

http://www.superantispyware.com/index.html

I second micky77 comment.

No one program has the possibility of finding everything out there. That’s where Superantispyware (also written as SAS) and MAlwarebytes Antimalware (MBAM) come into play. They increase the chance of finding nasties.