Considering there is no other CA product installed on this machine:
1. Completely delete the CA folder under <drive_letter>:\Program Files and <drive_letter>:\Program Files (x86);
----- Please make sure to check if there is no other CA folder on other hard drives/partitions on the same machine.
2. Completely delete the CA and Computer Associates keys in Registry under HKEY_LOCAL_MACHINE\Software and HKEY_CURRENT USER\SOFTWARE;
----- Under HKEY_LOCAL_MACHINE\Software and HKEY_CURRENT USER\SOFTWARE, on 64bit systems, there is a subkey called WOW6432Node to host 32bit keys. It is important to delete from there as well.
3. Check under services.msc if there is any CA service left. If there is CA services, then please delete them from Windows Registry too.