If pages load slowly or do not open, it is very likely that you are using DNS servers problematic. Since change by hand is difficult, better uses utilities such as DNS Jumper.
DNS Jumper is a free tool that allows you to change the DNS servers used by your computer by other different. To add the Spanish translation and new Jumper DNS servers, click the icon and press the blue i Update Check.
DNS Jumper has a list of more than thirty free DNS (from Google to OpenDNS) and an option to change the addresses by hand. Fastest DNS function runs a speed test and select the DNS with lower response time.