There is a pretty good answer over here on the MSDN Forums: MSDN Clickey
The crux of the answer is:
According to the description of your problem, you failed to install Visual Studio 2010 Service Pack 1.
The error 0x800c0005 may occur if certain dynamic-link library files (.dll files) are not registered correctly or if there is a firewall between the computer and the Internet that does not allow HTTPS (SSL) connections.
Here are my suggestions:
- Please download the ISO files of Visual Studio 2010 Service Pack 1 from: http://go.microsoft.com/fwlink/?LinkId=210710
Since I find that you installed Visual Studio 2010 Service Pack 1 via a web installer, I recommend you download ISO file and install it.
- Extract the ISO files to your local hard disk.
- Complete or dismiss Windows Updates before installation (but turn on Windows Update service).
- Clean up your “%temp%” folder (Start>>Run>>%temp%).
- Check if there are any anti-virus or antispyware applications running. Make sure they are turned off during installation.
- Run the setup file with Administrator privileges: Right-click the installer > Run as administrator.