Why my windows show your browsers preferences has changed message?

Hi guys, I use acer laptop with windows 7 in it and it is showing this message whenever I’m opening it that “your browser preferences has been changed and click yes if you want to keep it and no if you want to set the default settings again” this is the message I get every time when I open my PC.I don’t know why it shows this message please help me solve this.Thanks in advance
