Jim,
As you are probably aware, the first time you start Links after installation, it will ask to insert the CD to "verify the media" (or something like that). Afterwards, it shouldn't ask again. If you are running into this upon each start up, there are a couple of things you can check/do to resolve it:
1. Apply a No-CD patch that can be obtained from
http://www.gamecopyworld.com
2. If you have a card reader or other drives on your computer, try re-assigning the drive letters to a higher letter, especially any drives that may be assigned "G:"
There are threads here and at Links Corner that discuss details further, in case my summary doesn't lend itself to a solution. Here are a few threads you may want to read:
http://www.lspn.net/forum/viewtopic.php?t=1111
http://linkscorner.org/forum/viewtopic.php?t=16472
http://linkscorner.org/forum/viewtopic.php?t=19797
http://www.linkscorner.org/forum/viewtopic.php?t=17372
Armand