I was going through a Web design tutorial and it suggested that I should tryout Web pages on different browsers. I downloaded Firefox but at the end or just after, the computer hung up and would not reboot. Black screen with flashing cursor. Did all the normal things like removing battery and peripheral devices and power connection.held power button down for 60 seconds. Reconnected battery and power. Switched on but exactly the same response. Just answer said it was a hardware problem as the power up was not kicking in. Have ordered a refurbished hp model but am concerned that the same thing will happen.