Gateway nx850 drops internet conection

Ok here is my problem. I upgrade my wireless router to a DIR-615 dlink. Well lo and behold, nothing happens to my Dell d610 laptop, my desk top that is on the other side of the house, my Xbox, her Wii. They all work fine no drop outs, the computer on the other side of the house drops once in a blue moon. But that is understandable since it has several walls in the way. But my Wife's Gateway nx850 laptop drops very sporadically and very often. It will go a couple of hours with out a problem then boom drops connection, takes forever to reconnect. So I am wondering what could be causing this problem of drop connections only on that computer. Also she normally uses it in the same room as the router and signal strength is always 100%.

 

Well I have tried the turn the router off and on again. That worked for her for about half a day. Then it started droping again. The problem that makes this frustrating is that the stupid thing still says that it is connected when it won't load the web page. I have done the command screen and pinged not only the router but also other websites. The time is in ms is the same as on my laptop or better than the dell. It is way better than the computer that is on the other side of the house.

Could her built in wireless be incompatible? Is it going bad? The computer is about 3 years old and change. Has anyone else had incompatibility issues with Gateway built in Wireless and Dlink routers????