CC 2014 does not need serial number, it is based on Adobe ID. If the payment is up to date & CC is active then you should not be asked for serial number.
Please refer toCreative Cloud applications ask for serial number
Idon't know which operating system you are working on so i am giving you some steps windows and MAC OS:
Windows:
In windows 7 navigate to following location:
/windows/system32/drivers/etc
1. look out for "Hosts" file
2. Open it with notepad
3. Check if you have any entry for Adobe
4. Remove the entries and try again launching any product from CC
Mac:
1. Please click on "Go" and navigate to /private/etc
2. Open "hosts" file and check out for any entries for Adobe.com
3. Remove the entries and save the file
4. try again launching any product from CC
http://helpx.adobe.com/x-productkb/policy-pricing/activation-network-issues.html.
Please let us know if it worked.
Regards,
