While i go to a lot of trouble to make sure that the programs used and the advice given here is bulletproof, you cannot hold me responsible for any loss damage or corruption caused by following any advice given or installing and running any of the software recommended on this site. However, it is the way i run my PCs (i have 5 or 6 altogether at home) so I'm not suggesting anybody do anything that i wouldn't do.
The Internet, problems can happen at any time, and all sorts of things can cause a problem, but there is a couple of simple things to try before hitting the panic button.
I think everyone has seen the 'web page cannot be displayed' error message. This can be caused by the modem and/or router, these devices have a lot of software inside them now, and this software (like any software) can get a glitch or go completely haywire, and this is often the cause of 'this web page cannot be displayed' message. You can try restarting your modem and/or router, this is as simple as unplugging the unit and waiting 30 seconds before you plug it back in. The reason you have to wait 30 secs is because of the capacitors inside the modem/router, capacitors hold charge for a while, so if you turn it back on too quickly it will start in the same messy state and you might not have the internet on again. After 30 secs all the capacitors will have run out of power and the unit will start fresh. Once plugged back in they usually take about 1 minute to 'boot up' and then you should have the internet working normally again.
If you still don't have the net it could be a problem with the internet properties. These can be found by right clicking on the Internet Explorer icon on your desktop and selecting properties from the list that pops out, or go to the control panel and select Internet Options. You can delete all of those nasty temporary internet files you've heard about, then select the Security tab and check that all the zones are set to default. If you are still having trouble connecting to the internet you may have to call your Internet Service Provider to check that everything is OK with their end, it doesn't happen often but it does happen, especially with some of the smaller providers.
If all else fails you may have to call an IT professional to diagnose the problem for you, however most of the time you can get out of trouble with these simple steps. best of luck and as always
Leo Notenboom is most well known for his computer help site 'ask-leo.com' and it has been an extremely valuable resource over the years, so if you have a problem or a question that i havent covered here i encourage you to visit him. Also he has generously made available his tips on Internet Safety - its well worth reading and could save you from disaster