Equipment faults

Issues can range from modems, routers, computer firewall's, viruses, filters or even other telephone equipment connected to the ADSL line.

Modem/router faults - Try resetting your modem/router, as with most electronic equipment, they can be prone to lock-ups (freezes). Make sure all your settings are correct; these can be confirmed with your Internet Service Provider.
You could even have a faulty modem/router or filter.

Firewall's - This is software that protects your computer by blocking and permitting programs access to your computer. Recent upgrades could possibly block you access to the internet.

Viruses/Spyware - These are programs that can infect your computer and can even prevent your browser from working. Make sure that your anti-virus software is up to date.