Check Dells site
http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=19&l=en&s=dhs&ServiceTag=&SystemID=INSPIRON1440&os=WLH&osl=en&catid=&impid=
Also, please note that when migrating from Windows XP to Windows 7 you will not have an "in place upgrade" option. You will however have the option to select "custom" install when prompted. The Windows 7 install process will then copy all of your data in "My Documents" over to a Windows.old folder within Windows 7 itself. All applications and documents stored in other locations will have to be reinstalled / transferred manually.