Several programs can block that port. Candidates are:
- Skype
- Web Deployment Agent Service (can be stopped via Start -> [-> Run] -> services.msc)
- World Wide Web Publishing Service
- IIS (if you have it installed)
- TeamViewer
VMware (in VMware Workstation go to Edit>>Preferences>>Shared VMs, and Disable Sharing or change the port)
Web Deployment Agent Service and World Wide Web Publishing Service can be set to manual start to keep them from running. Stop or change these services from an account that has administrator permissions.
Skype and TeamViewer can be configured not to use port 80.
For Skype Go to Options > Advanced > Connection and un-check "Use port 80 and 443 for incoming connections"
For TeamViewer Go to Extra > Options > Advanced and un-check the similar message as above.
EDIT: I made the post a community Wiki, so if people find other programs, they can add them here.
