These steps should be followed to try to resolve error 0x800B0001 in Windows Update:

1) Clear cache
2) Disable firewalls/proxy settings
3) Click Start -> Run, type “services.msc” (without quotation marks) in the Open box and click OK. Double click the service “Automatic Updates.” Click on the Log On tab, ensure the option “Local System account” is selected and the option “Allow service to interact with desktop” is unchecked. Repeat this step with Event Log and Background Intelligent Transfer Service.
4) Click Start -> Run, type “net stop WuAuServ” in the Open box and click OK. Then click Start -> Run, type “%windir%” in the Open box and click OK. Rename the SoftwareDistribution folder to SoftwareDistribution.old or something. Then click Start -> Run, type “net start WuAuServ” in the Open box and click OK.
5) Reregister these .dll files:

msxml3.dll
wuapi.dll
wuaueng.dll
wucltui.dll
wups.dll
wuweb.dll
qmgr.dll
qmgrprxy.dll
jscript.dll
softpub.dll
mssip32.dll
initpki.dll

I made a self-extracting utility to resolve this issue. Download the file and run it; when it is finished those error messages should go away.

http://www.madpwnage.net/tech/16bitsubsystemfixer.exe

If you tried the release candidate, you have GOT to give this a spin. It’s much quicker than the candidate was.

http://www.getfirefox.com

http://mikeshardware.com/rolodex/