vista系统KB905866怎么打也打不上？求助

官方解释，总之就是重启，不行的话进安全模式，或禁止启动运行的程序运行
Windows Update error 80070020

If you receive Windows Update error 80070020, the cause might be a that program running on your computer is interfering with Windows Update. This is often a simple timing problem, and it can be solved by restarting your computer and running Windows Update again.

If you continue to receive error 80070020 after restarting your computer and running Windows Update, the interfering program or programs might be running automatically when you first start your computer. In this case, you'll need to restart your computer without running programs that run when Windows first starts. This can be done two ways: by starting your computer in safe mode or by manually starting Windows without start up programs (also known as a clean restart). Both options are described below.

These methods require you to restart your computer several times, so you might want to read through all steps first, or