It worked 'normally' until I downloaded the following Microsoft updates tonight :
Windows Genuine Advantage Validation Tool (KB892130)
Security Update for Excel Viewer 2003 (KB914451)
Cumulative Security Update for Outlook Express for Windows XP (KB911567)
Security Update for Windows XP (KB908531)
Cumulative Security Update for Internet Explorer for Windows XP (KB912812)
Security Update for Windows XP (KB911562)
Security Update for Windows Media Player 10 for Windows XP (KB911565)
Windows Malicious Software Removal Tool - April 2006 (KB890830)
Did any of these cause this problem or is it something else?
Thank you for your help with this.