These tech giants have seen their shares and valuations drop in recent times.Buying a stock on bad news may sound like a pretty bad idea at first. Why would you want to pick up shares of a company that's facing a stumbling block?It's important to consider the news carefully. If a particular company has been navigating rough waters but has a solid long-term story, it could be a fantastic moment to buy. That's because you'll get in on this potential long-term winner for a better price.Two technology companies ...