That would be a function of your anti-virus program.
Norton and other anti-virus programs have settings that affect what is scanned.
Review your anti-virus help file.
Also, helpful advice here... http://www.cpearson.com/excel/newposte.htm

Signature
Jim Cone
San Francisco, USA
http://www.realezsites.com/bus/primitivesoftware
(Excel Add-ins / Excel Programming)
"ss"
<yamxs750@blueyonder.co.uk>
wrote in message
When I open an excel sheet it "requests a virus scan" any way to switch this
off as I move between different spreadsheets and it slow everything down for
me.
thanks