after several months of use, I am still happy I bought it. Windows Ready Boost works well, and is very easy to use.

Because the card does pertrude from the machine by 1/16", from time to time i accidentally eject the card by bumping it, which is not a good thing when Ready Boost is running becuase it crashes the system.

I don't know much about computers. It would help to have directions with how to install and use this. It works ok when I have the computer booted up but if I have the card installed when I boot, it doesn't boot to windows. I don't konw if that's how it...

An ExpressCard is not directly compatible with the PCMIA card slot that the Latitude D420 comes with. There are caddy's / adapters that look like they would enable use of ExpessCard with a PCMIA card slot but that is an extra item that one must buy to...