How do you delete Internet Explorer?
Answer.... you don't!
There are ways to disable parts of it, and even remove other parts of it, but the fact remains that Internet Explorer is a key part of Windows itself.
It can't be completely removed, and still have Windows work.

Here are a few good Anti-Virus programs you can try for free...

AVAST 4 Home Edition Antivirus
http://www.avast.com/eng/download-avast-...

AVG (free)
http://free.grisoft.com/doc/2/

AVIRA (free)
http://www.free-av.com/

Not all antivirus tools are the same; if you find that the one you use isn't working to your satisfaction, you should do some research and try an alternative.