There's nothing wrong with reinstalling the operating system when things get messed up. When I stared with Linux I would reinstall the operating system frequently. Knowing that you can do that gives you a way out if you break stuff. You can do a lot of experiments and then reinstall the operating system.
Regarding the CD access problem I would look at the permissions settings on /dev/cdrom.
$ ls -l /dev/cdrom
lrwxrwxrwx 1 root root 3 2006-09-05 19:23 /dev/cdrom -> hdc
$ ls -l /dev/hdc
brw-rw----+ 1 root disk 22, 0 2006-09-05 19:23 /dev/hdc
Here you can see that /dev/cdrom is just a link to /dev/hdc. Links cannot restrict access. They always have 777 as their permission setting. They simply pipe access to another file. The permissions on the file that the link points to will control access to the actual file. We already established that the link points to /dev/hdc. The permission settings on that file will control access to the CD drive. We can see that /dev/hdc is owned by the user account "root" and the user group "disk". The group permission setting on /dev/hdc is rw. This will allow any user account that belongs to the disk group to have read/write access to /dev/hdc.
Now check the group membership of the user account that you want to use to access the CD.
users disk lp audio video
You can see that the user account belongs to the disk group among others. Membership in the disk group provides permission to use the CD drive. In practice this user account is able to burn CDs and DVDs, play music CDs, and is fully capable of using the CD/DVD drive.
So that's the first thing to check.
If this is the problem then you can add your user account to the disk group by using the usermod command. This command is a bit primitive. When we add the disk group to the user account record we will also have to repeat all of the other user groups that the user account already belongs to.
1) Log in to the root account.
2) See what groups the normal user account already belongs to.
3) Use the usermod command to add the disk group to the user account record.
If the normal user account is named "myaccount" then this would be the procedure.
root> groups myaccount
myaccount : users lp audio video
root> usermod -G disk,lp,audio,video myaccount
root> groups myaccount
myaccount : users disk lp audio video
Note that you do not have to repeat the membership in the "users" group. That is because "users" group is the primary account group. In the usermod command we are only changing membership in secondary user accounts. This is controlled by the -G parameter in the usermod command.
More information about the usermod command can be found using usermod --help.