If you are being sent to a website u don't want it could be a few things if its only on some websites perhaps its just pop ups if it does it by its self all the time or without u doin anything you have your self some adware (incoming tech list) the first thing you should do is run a virus scan to ensure that this isn't a tag on of a more serious thing on your computer, most people don't know it but their anti-virus program is garbage if you got this problem in the first place it properly wont be removed by scanning, a good antivirus is avast (click the bottom left "Download") http://funadvice.com/r/15ehimjigll but by definition anti-virus programs can't catch everything you should also have SuperAntiSpyware (click "free edtion") http://funadvice.com/r/15ehimjijj1 and MalwareBytes http://funadvice.com/r/3judfk3jhs yes that is alot of programs but they are ALL FREE and this is the best combination of programs to protect you computer run a scan with all three of these programs and your computer will be clean
Hope this Helps :)
It might also be that there is a re-direct on that web site, depending on which one it is.
So if you, for example, type wikipedia.com you get re-directed to wikipedia.org. Because the wikipedia guys have their site at the dot org domain but they also bought the dot com name and just made it send all visitors to wikipedia dot org. This is also possible with un-similar names. You could buy a domain that reads church-of-frigidity-girls-convent dot edu and have it re-direct all visitors to sodom-and-ghomorra dot com.
restart the computer and if it still does it there must be a virus so then you call a computer person to take a look at it
I used Malware Bytes and recommended it to others with stubborn virus issues and it works.
Sounds like adware or malware.