Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
While I agree the problem is with Gmail, lets focus on your HP computer for now.
How did or do you access gmail on your HP computer. Do you use a program such as windows mail, outlook 2010, thunderbird.. Or, do you only ever access gmail through a web browser?
Also, what version of windows do you have on the HP computer?