Maybe start with this:
First go to Start/run, and type Msconfig. Go to the startup tab, uncheck New.Net application, and click OK.
Now reboot, and the program will not load again with Windows, preventing the recurrence of your error message.
Now go to Software add/remove, and remove New.Net application there.
Don't attempt to remove the dll manually, because that may cause the loss of your internet connectivity.
If uninstalling doesn't get rid of the dll (it happens), try this:
First, you will need to locate the New.net ".dll" file that is on the computer. Do this by doing a search for "newdot*.*".
The file will be located in your "Windows" folder. Once found, make note of
the actual filename which should look something like this:
Example: newdotnet2_90.dll
Close the Find or Search window then...
Click Start
Click Run
Copy and paste in the following line (adapting the name of the file, if required)
"rundll32 c:\windows\newdotnet2_90.dll,NewDotNetUninstall"
Click OK
You should then see a small window asking if you want to uninstall the New.net application. Click Yes. Once this is done, restart your computer. This should keep the .dll from loading up at startup of your computer.
More info on the site BrianF mentioned.
Good luck, Tony