Betty Ashdale asks: every night I set my computer to run antispyware software (Adaware) and an antivirus scan (Norton). My friend says I don't have to run them every night, but I would prefer to be safe than sorry. What do you recommend?
It is not necessary to run an AV scan unless you have reason to suspect infection. The AV software will scan files as they are written to disk.
If a virus is not detected at that initial stage it will be scanned on each subsequent occasion that it is accessed. The result of the scan will depend upon the AV product having a signature for the virus. Therefore the crucial issue is the frequency of signature updates. As Norton AV performs automatic updates you do not need to worry about this.
Spyware is a somewhat different issue. I personally run a scan every weekend. Adaware is fine but limited to advertising spyware. I would recommend that you use a broad-spectrum antispyware package such as Microsoft's free offering or SpyBot Search and Destroy, which is also free.