you can connect via a proxy server - do a google search for proxy - there are servers all over the world in various countries - it comes in handy especially when you want to visit sites that only allow access to ppl from a certain location.
not all proxys are always work 100% of the time and it can affect your surfing sped but it will hide your IP.
to setup the proxy on your browser>> tools: internet options: connctions: lan settings - input the ip address and port of the proxy and then check your surfing - i had a list of about 30 the other day that i was going through and only found one that worked well
Yes changing ISP or reconnecting will change your ip, south africa uses dynamic ip so ip changes with each login, simply disconnect and reconnect, but seriously man if you are going to places that you need to hide your ip/history then you shouldnt be going to them in the first place as you dont sound too clued up.