Your dad should first have checked the Dell website to make sure that Dell supports Windows 7 on that model. You've been lucky if all that's missing is the video driver, but Dell is the only place you're likely to find drivers that work.
Unfortunately, I have checked and Dell do not support Windows 7 on the Inspiron B130, which means they have no Windows 7 drivers, and I doubt you'll find a video driver from anywhere else that works properly. You can check here for yourself:
As you can see, the only Windows drivers they have are for Windows XP. The only way you'll get the display working properly again is by putting XP back on it & installing the XP video driver.