Problems with Dell Latitude D620 laptop

I have owned a Dell Latitude D620 for the last few years. Lately, i have realized that my 9-cell battery is only charging to 84% (4 weeks old), and it only gets about 1.50 hours on full charge. Also, at random intervals, the LCD screen flickers and becomes blurry. All settings are default and there have been no modifications, here is my computer information.

Dell Latitude D620
Intel Core 2 Duo T7200 2.0GHz
2GB RAM
256MB Video Memory (nVIDIA Quadro 110)
Microsoft Windows XP Professional Service Pack 3
60GB 7200RPM Hard Drive Disk
Wireless G Ethernet Adapter
Gigabit Ethernet Adapter
9-Cell Battery

Can someone please help me as to what is wrong with this computer! Thank you very much!

 

First of all, where did you get that 9-Cell battery? Was it from Dell or somewhere like eBay? How much of a charge did your original battery hold when the machine was new? Second, do issues with the LCD screen crop up when you hook the machine up to an external monitor?

 

I ordered the 9-cell directly from dell, it cost about $200 and it was new. The original battery was a 6 cell and only held a charge for 1.50 hours. No, the issues with the LCD monitor are happening as i type at random intervals when not hooked up to another monitor. I originally thought it may have been a GPU problem. Also, my computer will start to flicker and then IntelPROSET wireless will pop in (i have defaulted to WinZeroConfig) and say that no wireless networking device could be found, then the keyboard stops working along with the touch pad. I think it might be the motherboard, i dont know however.