Please check the recent update in my computer as below:
Definition Update for Windows Defender - KB915597 (Definition 1.51.937.0) 2009/2/24 02:23am
Definition Update for Windows Defender - KB915597 (Definition 1.51.768.0) 2009/2/20 06:26pm
Definition Update for Windows Defender - KB915597 (Definition 1.51.627.0) 2009/2/17 12:39pm
KB951847:Microsoft .NET Framework 3.5 Service Pack 1 x86 語言套件 2009/2/16 01:11pm (language set)
Definition Update for Windows Defender - KB915597 (Definition 1.51.484.0) 2009/2/14 09:01pm
KB890830:Windows 惡意軟體移除工具 - 2009 年 2 月 2009/2/11 06:31pm (malware removal tool)
KB961260:Windows Vista 的 Internet Explorer 7 積存安全性更新 2009/2/11 06:30pm (for security update)
KB960715:Windows Vista 的 ActiveX Killbits 更新彙總套件 2009/2/11 06:29pm
KB905866:Windows Mail 垃圾郵件篩選器更新 [2009 年 2 月] 2009/2/11 06:28pm
Definition Update for Windows Defender - KB915597 (Definition 1.51.391.0) 2009/2/10 08:33am
After updating, the computer started to present a window to ask if I allow the the programm execute every time when I tried to use some software. This change, I think, may be caused by "KB961260", "KB960715" or "KB890830".
Is it possible one of these updates prevent the computer from executing ccleaner.exe?