I'm at work, connected to the internet via my cheap laptop. I want to buy the game now (full version/all games), online, and load it into my laptop...(Slow day at work

Must I buy the game twice ???
My CD drive in this laptop is toast, so I have no way to copy it or burn a CD.
Can I log on from my home PC and download it again ???
Can I email it to myself ???
I dunno ?
Any advice is appreciated... I have a credit card ready, in hand.

Thanks in advance !!!