I'm not with Laminar Research, just a fellow simmer in the UK.
There are two issues here a) installing XP11 into your new PC and b) actually running your copy of XP11 once you have installed it? Either way you will at least need a DVD ROM drive to run XP11, as Disc No 1 always has be loaded to activate the software!
Your options are:-
1. Use an external DVD drive to load all of XP11 discs and keep the software activated once running
2. Install an internal DVD drive into you PC, to load all of XP11 discs and keep the software activated once running (assuming that your PC case has the space for one)?
3. Download a demo copy of XP11 directly from Laminar Research, but with this option, you will still need some sort of DVD drive connected, so that Disc No 1 is always available for activation purposes.
Hope this helps