Looking for a CD key for (or earlier versions like 1.0) usually involves locating the physical retail packaging from the late 90s or early 2000s, as these versions pre-date the modern Steam system. How to Find Your CD Key
Did you own a legitimate copy of CS 1.1, or do you remember the struggle of the "Invalid CD Key" error? Let us know in the comments! cd key cs 1.1
Printed on a white sticker on the outer cardboard packaging. Common Issues with CS 1.1 CD Keys Looking for a CD key for (or earlier versions like 1