Need to re Install Tiger. CD Drive not working

Here is some background info that led to my current dilemma. I asked
the techs at "macros X.com" their answer is included.

MY QUESTION:
Where to begin. Over the weekend I installed VLC which worked fine for
one day. After that no video.

In the interum, I upgraded to 4.1.1 and QT 7.4 Didn't help the VLC
problem but my system was working fine.

So last night, upon the advise of some online pros, I installed
Pacifist and overrode QT 7.4 with 7.3. Again it didn't help the VLC
problem but otherwise, the only problem I noticed was Camino kept
crashing. (I do notice the "Pacifist" option Open Apple Install Discs
is greyed out.)

TODAY
I boot up and I can't access Mac Mail or System Preferences. Plus the
icons on the top right finder menu are gone. I did locate the latter
in my HD and all the icons are there, but when I try to launch them
individually, it will launch for about 2-3 seconds (I can see all the
data) then closes.


THEIR ANSWER:
sorry to hear about your mess, The best thing to do in this situation
is to archive and install the operating system. You have the option of
saving the user data and the network settings (your user data will not
be effected).

QuickTime is a major framework of the system (a building block), it
cannot be simply replaced with a older version. Once you install a
newer version of QT, it changes several thousand files in the OS.
Overriding the installer to put in an over copy changes just a handful
of these needed files, everything else is looking for the newer copy.

This may or may not be the only thing you have to do to get everything
back up and running but it is where you start.

Take care ]

Now it seems my computer does not recognize CDs. The icon doesn't
appear on the screen and a message said the computer couldn't read the
disc. I've used these discs before. Now when I tried the Tiger
install disc, it just ejects after 1-2 minutes and again, no icon
appears. I'm on an Imac G4, which otherwise runs well. Or did.

Summarily I can neither back-up nor use the install disc. I don't
know if it's a drive problem ,or a screwed-up-system problem, due to
the QT over-write. Any help would be appreciated.

If I need a new dvd or cd drive, any suggestions on a decent
inexpensive one?

Thank you.