What Is It?
Norton Security - symlcsvc.exe

What Does it Do?
This is one of MANY processes that are used by Norton Security (AV + Net Security) If its under the appropriate directory you'll have nothing to worry about. If you're experiencing slowdowns you'll want to upgrade your hard drive and/or your RAM. Norton is a resource hog.

Virus Precautions:
The normal location of this file is in this directory: C:Program FilesCommon FilesSymantec SharedCCPD-LC