Dell has always sent there LCD screens with the LCD inverter built in so more than likely if you wanted to do it yourself you would have to go to this link to order the LCD, http://cgi.ebay.com/Dell-D620-D630-LCD-Screen-14-1-LTN141WD-L01-RF-/110666384593?pt=LH_DefaultDomain_0&hash=item19c43b04d1
Then here are the instructions on video how to replace it.
If not you would have to take it to a computer repair shop to repair this problem. Only if you are not easy about taking it appart.
Usually the parts is cheaper and cheaper to repair it yourself. If you have someone do it, it can get a little costly. That's why I am giving you the alternative option.
The good thing is that it's not to dificult to do the do it yourself task I will also say if you decide to just by the LCD and have someone put it in it's cheaper to do that as well.
If this advice is helpful, please click ACCEPT. It is the only way I will be personally compensated for my time, and it will not affect the amount you have already agreed to pay. A Bonus is optional.