Information about your country extracted from your IP address. So you must change your IP address. If you use Internet Explorer just start Mask Surf and that's all. Select menu "IP test" to see what country you got.
If you use Firefox you must setup it for anonymous work by checking "Apply anonymity to".

Please launch Internet Explorer, select Tools->Internet Options->Connections tab->Lan settings(or Settings for dial up connection)->Proxy Server. Uncheck "Use a proxy server for your Lan"(or set your default proxy settings if any).

In fact you can use with Mask Surf any internet program that supports socks proxy. You need to set proxy 127.0.0.1 in protocol "socks" and port (9050 by default) in the beginning of anonymous work and unset it in the end. Most Internet related programs has support for socks proxy. If the program has no support for socks(like Opera browser) than you cannot use it with Mask Surf Pro. Use Mask Surf Everything instead.

And pay attention that at anonymous work the information can be transferred more slowly than at normal work.