Dear friends

I would like someone to help me with this problem that happened just some days ago.
I have Windows XP Home SP2 installed.

- I open the Windows Update Web page, do a serach for new updates and the opens another page telling me that I have programas not registered.
Then I choose to register, goes to 100%, perform another seach, Same thing again...

- Windows Defender gives me the error 0x80040154 when I check for new updates.

- I can't install anything that uses Windows Installer (*.msi). Message: "It's not possible to acess the service Windows Installer....."
This service is running in my computer.
I've tried "msiexec /unregister" followed by "msiexec /regserver". This doesn't solve the problem.

- I can't see or acess my network.

- My printer is always offline. So I can't print anything.

I'm the sole user of this computer.

I can't restore the system for 10 days behind.

I can't use Safe Mode with the user Administrator.

I've run a full search for virus and spyware. Nothing major was found.

Could this be a problem of permissions in the registry.
Should a re-installation repair this problem ???

One more thing. When I'm trying to see the dependencies of the Services, a message appears: "Interface: Class not registered".

I have joined a printout of HijackThis
Thank you for your attention

Edited:

I have removed your Hijackthis log as we do not attend these logs in the forum. Go to the Malware forun, and once you have received a clean bill of health the you can post in this forum if necessary.