For antivirus software I have been using AVG by Grisoft for as long as I can remember. Efbell mentioned windows built-in spyware, it's called Windows Defender and has been available since Vista I believe. It's probably as good as any other malware/antivirus software.

http://www.microsoft.com/security/pc...-defender.aspx

Can't help with what computer, have not bought one for 25 years.