If you registered the game online, you can get your serial number off the EA Games website (not the sims website). Just log in (same username and password) and go to your profile. The serials are listed there. Also, you will be able to find the serial in the registry (if you know where to look). I don't have the instructions for this off-hand but you could Google for it.
Answers & Comments
Verified answer
Try this,
The Sims2-Nightlife Expansion Pack:
E7LL-A98Z-V2KG-VX6T-Z7R3
86X7-SQDL-J5TJ-5FKJ-P7EZ
A78Y-Z2EF-8LNR-FAZ4-SCP2
9NNN LNVZ YH98 79TN 72EW
3S7X-SVEA-GF3U-LV7T-DBHP
3S6W-QMS6-BRXL-34GC-ENFR
5AWW-XWJ3-2XVD-DVXG-XTRE
2KB3-CQNS-KLHY-QSYV-G5F9
Sims 2 Nightlife
For the best answers, search on this site https://shorturl.im/axuyc
If you registered the game online, you can get your serial number off the EA Games website (not the sims website). Just log in (same username and password) and go to your profile. The serials are listed there. Also, you will be able to find the serial in the registry (if you know where to look). I don't have the instructions for this off-hand but you could Google for it.
That sucks. Nothing you can do about it. Sorry! Contact EA. But i doubt they will be able to help.
It sounds like you'll have to buy a new copy. Sorry.