Hello, Chwat! I am unsure if there are any online stores for pc games out there where you can purchase a digital copy of Battlefield Vietnam... I know Steam doesn't have it, Origin too as far as I know.. As for me, I bought my CD copy in local store long long time ago. I'm sure you can find a lot of sell suggestions for used and new ones on Ebay, Amazon, etc.
If I understand you correctly, the only reason you can't get in the game is the absence of CD reading device? I'm sure in our modern times there are a lot of cheap or even free options of obtaining one I hope you will overcome these obstacles and join us in this great game soon!
But don't forget that installing a clean game is not always enough, for more info check our guide here: Files & Guide
It's quite common nowadays that Battlefield Vietnam is not running well right after the installation so it requires some additional steps to get it working. If you describe your situation in more details, we might be able to help you to get it working.
Right now I can advise you to get v1.21 patch to be able to connect to our server. And since you're saying that it's not launching at all, I suppose you are using Windows 7 or higher? If so, you might need to install a NO-CD crack to get it working (don't forget to install v1.21 patch first). As always, all instructions how to do it you can find here: Files & Guide
If you still unable to launch the game, don't hesitate to provide us with more info!