Excel, Word, and Outlook have started hanging on a Windows XP machine. When it happens, the keyboard and mouse are completely non-responsive. The only recovery is to hold the power switch in to turn off the PC and then restart.
I see application hang messages in the Windows application log. Those started last December and have increased in frequency over the last week or so. Now happening two to ten times per day. Mostly in Excel, but that is what the user uses most. The hangs do NOT occur at startup of the app. They happen while the app is in use and sometimes when closing it.
Dell Precision Workstation 370, Windows XP Pro SP3, Office 2003 SP3. PC has the latest BIOS.
No particular new software since December - just updates to Windows, Firefox, etc. Kaspersky Internet Security full scan reports that the PC is clean.
Any ideas what could be causing this and how to troubleshoot it?