VGA driver

Hello,
OS Name Microsoft® Windows Vista™ Home Premium
Version 6.0.6000 Build 6000
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name UDAY-PC
System Manufacturer Dell Inc.
System Model Inspiron 1420
System Type X86-based PC
Processor Intel(R) Core(TM)2 Duo CPU T5550 @ 1.83GHz, 1833 Mhz, 2 Core(s), 2 Logical Processor(s)
BIOS Version/Date Dell Inc. A07, 2/3/2008
SMBIOS Version 2.4
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume2
Locale United States
Hardware Abstraction Layer Version = "6.0.6000.20500"
this my lappy discription.
i am not getting the VGA driver for my system