Hello. I have three different custom built machines with old, updated Windows XP Pro. SP(2 and 3) that have ATI Radeon video cards (9600 AIW, 9800 Pro AIW, and HD 4870) and ATI Catalyst drivers and its Control Center (latest to the old legacy versions).I noticed sometimes they won't/didn't security lock correctly from their defined screen saver's times. Even press winkey+L does not lock. I did see winlogon.exe running in XP's Task Manager. The only way to fix this problem is to reboot the computer.Is this a known issue and is there a way to fix it without rebooting like restarting winlogon.exe process? It seems like this is related to ATI video cards and its drivers in XP Pro.? I never see it with XP systems without ATI video cards like NVIDIA and onboard Intel video chipsets. And yes, I scanned for malwares with multiple updated softwares. They all showed my systers as clean. Event logs don't show anything about winlogon.exe.Thank you in advance. :) Ant @ Ant's Quality Foraged Links (http://aqfl.net) and The Ant Farm (http://antfarm.ma.cx).

Hi Ant Dude, 1. You may uninstall and reinstall the display driver from device manger and check results. Steps to uninstall the device:a. Click Start, type devmgmt.msc and press enter.b. Locate display devicec. Right click on the device and select uninstalld. Also place a check mark beside the option “delete driver files for the device”e. Install the latest drivers for the device from the manufacturer’s website 2. Create another user account and check the results. How to create and configure user accounts in Windows XP:http://support.microsoft.com/kb/279783 Regards:Samhrutha G S - Microsoft Support.Visit our Microsoft Answers Feedback Forumand let us know what you think.I have tried uninstalling, running driver cleaner tools, and clean reinstalling from scratch in the past. They did not help. Switching accounts doesn't seem to help either.Ant @ Ant's Quality Foraged Links (http://aqfl.net) and The Ant Farm (http://antfarm.ma.cx).