I did what DWong did by reverting back my machine.config file back to the default one.
I
got this problem in SQL Server 2008 R2, which was previously installed,
after installing Visual Web Developer 2010 Express via the Microsoft
Web Platform Installer on a 32 bit Windows XP box.
Instead of location:
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\
find
out your latest framework version of .net like v3.0 or v3.5 or
v4.0.30319 whichever is latest and then try to install. It worked for me
like a hell!!!
Server 2008 Standard x64, used to host SQL 2005 x64, was uninstalled,
rebooted, and failed to install SQL 2008 x64 with this same error
message. I found the machine.config file where indicated below, opened
it in notepad, and simply removed the entire <system.servicemodel>
node and saved it.
Resolved
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config
The machine.config file had the <system.serviceModel> node, I reverted back to the machine.config.default file.
I
found this out by looking at C:\Program Files\Microsoft SQL
Server\100\Setup Bootstrap\Log\...\Detail_LandingPage.txt installation
log
Steps :
in run command
paste the below line and hit enter
notepad C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config.default
Select all and then copy all the file contents.
Then agains open another file
notepad C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config
Paste the selected and copied contenets here save and install the same again it will work now.
or if not solved repeat the same for latest versions i.e. 3.5. and 4.0 you have installed with your system.