AVG refers to a popular anti-virus solution from Grisoft, which is available for free. Grisoft also offers free anti-spyware/rootkit protection.
You should immediately install AVG on that freshly formatted PC.
(Temporary) Files you should always securely delete. Such as the ones created from web browsing activity, and used by many applications. Said files pose a threat to privacy. Clear your cache!
"Temp? I bet Josh has a lot of temp."