Trouble With Radar

Until recently I have used the Nexrad radar from Wunderground.com as my main weather radar. Recently, the computer only downloads about 1/2 inch of the top of the radar screen, then a series of broken lines. And then just a black screen below that. I have also noticed that if I am attempting to download a series of pictures all at once, the tops of the pictures will be shown and then a blank screen at the bottom. I am running Windows 7 if that is important to know. The same Wunderground Nexrad radar downloads perfectly on my wife's computer which is on the same network, so I assume the problem is with some setting in my computer. I have considered doing a default reset, but I'm a little concerned about what all that might change. If anyone could help me with this, I would really appreciate it.

Thanks

Gill Fisher