I bought a used, older dell latitude d620 laptop. I don't know the password to log on, now I cant even use it. How can I get into the start menu to do a complete system recovery?

Go to a friends house (bring a blank CD or DVD), and download Offline NT Password and Registry editor, then burn it to disk using a free program such as PowerISO (which can burn ISO images).
Go home, boot from the CD (Use F12 at boot for the boot menu, then choose the CD/DVD drive).
There are many places online you can look up how to use Offline NT, and just blank out the administrator's user account password using it. Good luck!

If you're not talking about the Power On or Bios passwords, there are any number of password changing utilities for Windows XP available on the internet. However, you'd still need a source disk to do a fresh install. Or if you're planning on wiping the system anyway, get a Windows 7 disc and do a format/install.

Unless you can find someone who can clear the administrator password, your only choice is to reload the OS. If you can find friend with an OEM version (not retail) of Windows XP, you can make a copy of the disk and reinstall the OS using the COA key on the back of the Laptop. You can download the drivers from the Dell website.

This may work. You need a disk. http://forums.sqlmag.com/forums/aft/98693