It was five months ago that Silicon Valley venture firm Sequoia Capital famously showed its R.I.P Good Times slides to its start-ups. The message? Advertising markets are cracking and e-commerce and spending on technology deteriorating along with the economy, making it harder than ever for start-ups to raise funds.  But Nvidia, a U.S. maker of computer graphics cards, announced some welcome news March 10:  it is ready to invest from $500,000 to $5 million in individual start-ups in its search for innovative new graphics computing companies.Read more