Try checking your hosts file and running a anti-spyware scan. Porn websites and downloading free .mp3 music files as of my last knowledge in 2009 can cause spyware infections, such is of the signs as the following: you try to go to http://www.google.com and on typing and pressing enter you would be redirected to another website. when on one web site, your web browser skips to another site automatically.
Is your computer acting slow? Avoid using free music downloading programs such as Limewire or BearShare, and try avoid installing tool bars that might be offered upon installation of programs. First update all anti-virus, anti-spyware, anti-rootkit, anti-adware data bases and try doing scans with all of these. Install a firewall program; don't use the built-in default programs that come with Windows.
Do research and do Windows Update, but do research on the updates that you plan to install; only install manually, don't use automatic update. Download the Windows updates manually and install them manually. as Windows updates can conflict with other programs.
In safe mode, chkdsk c: / f / r /v at a command prompt, type y for yes if prompted to reboot. Upon reboot, Windows will check the disk for errors. Disk scanning for errors and scanning for malicious software one time a week is necessary. Also use the Microsoft Malicious Software Removal Tool. Zone Alarm is a good firewall, ad blocker also, and http://www.iptools.su.
Do Google searches on every program before installing. Also look for free programs that you burn to a blank cd to scan under the operating system. Assuming you're using Windows XP platform; Win 7, Win 8 and Win 10 are all crappy and use way to much memory. Also try Glary Utilities.
Try to do a ping from a command prompt on that specific web site.