...let the vendor know that Stardock does not allow the re-selling of used copies of their software and then buy a new un-used copy.
Edit: Re-reading Monk's post, he wasn't really saying that SD doesn't allow used copies period. Oops. Ah well, I'll leave the info below anyway.

Eh... well, technically that's not right, by my understanding. The software can be re-sold just fine. It's the transfer of serial numbers (not required to play the software as-provided in the box) that is not allowed without SD's consent. Then again, you might get the vendor to believe that he's not allowed to re-sell a game, but I wouldn't count on it.

Basically comes down to vendors being free to re-sell the game, but the buyers aren't entitled to support and patches.
YOU MAY NOT:
1. Copy and distribute the SOFTWARE or any portion of it except as expressly provided in this Agreement.
2. Sublicense, rent, lease or transfer your personal serial number without express written consent from Stardock.
3. Sublicense, rent or lease the SOFTWARE or any portion of it.
4. Decompile, disassemble, reverse engineer or modify the SOFTWARE or any portion of it, or make any attempt to bypass, unlock, or
disable any protective or initialization system on the SOFTWARE.
5. Copy the documentation accompanying the SOFTWARE.
6. Upload or transmit the SOFTWARE, or any portion thereof, to any electronic bulletin board, network, or other type of multi-use computer
system regardless of purpose (except as provided for above for “mods”).
7. Include the SOFTWARE in any commercial products intended for manufacture, distribution, or sale.
8. Include “mods” in any commercial products intended for manufacture, distribution, or sale.
So, yeah. Do your best to return the used copy and get a new one. Patches are substantial in SD land.