Windows Defender is NOT an antivirus program.
1. Uninstall Norton, using Norton Removal Tool
2. Download, and install ONE of these:
- Avast! free antivirus: http://www.avast.com...avast-home.html
- Avira free antivirus: http://www.free-av.c...load/index.html
- free PC Tools Firewall Plus: http://www.pctools.com/firewall/
- free Comodo Internet Security (firewall + AV): http://www.personalf...all.comodo.com/
NOTE. During installation, Comodo will also allow you to install AV only, or firewall only, if you prefer to combine one Comodo product with some other product.
If you decide to install Avast, or Avira, make sure, Windows firewall is turned on, or use PC Tools Firewall Plus.
If you decide to install Comodo, make sure, Windows firewall is turned off.
IMPORTANT! Make sure, you use only ONE antivirus, and ONE firewall.
After installation, update the program, and run full scan.
3. The error, you posted above is often caused by some infection, so when you're done with 1., and 2......
I suggest that you start a new topic in the Malware Removal - HiJackThis™ Logs Go Here area.
Before you post a log click on this link --> You Must Read This Before Posting A Hijackthis Log
this will give you a few preparations to make, as well as instruction for posting your Hijackthis log.
If you are still having problems after being given a clean bill of health from the malware expert, then please return to THIS thread and we will pursue other options to help you solve your current problem(s).