thanks again for your help with our systems this week!  I did purchase the snow leopard $29 upgrade but having trouble with the install.  When I insert the disk, the system seems to engage but within 30 seconds it rejects the disk.  Nothing ever shows up on the screen.  I tried restarting the  computer and I confirmed that the disk was installed correctly.  I had a brief conversation with a store attendant and they seemed to think that you must have 10.5 for the $29 upgrade to work.  Any thoughts?  Thanks for your help!

It is actually not true that you have to have 10.5.  I have moved many systems from 10.4 to 10.6.  

Try installing by doing the following:

insert the disc.  
Turn off the computer.
boot the computer holding down the C key.  
follow the install instructions from there.  

That will force the computer to boot from the disc instead of the internal hard drive.  Above all else, back up first if you have an external drive!  You never know what can happen during an installation.  That is very important.  

If that does not work, then either the CD drive is having problems or the disc could be bad.  But the later is very unlikely.
Scotty, first, thanks for your guidance!

I determined that the disk was fine because it worked on my daughters laptop just fine.

I also checked my disk drive with another disk and it appeared to be OK too.

I used your technique below and it did allow me to get one step further than before but once I typed in our password and selected the install button, the disk was ejected about 20 seconds later.  I've tried multiple times but no luck.  Any other thoughts?

If you think another visit is necessary, I would rather fund that than purchase additional software so let me know.  Thanks for your assistance!

Scotty,  Please let me know your suggestion.  Should we get you back over to help us get this 10.6 upgrade installed or do you have any suggestions for me...the email below is were I sit today.  Appears that the disk and disk drive are fine...my machine just want let the upgrade take.  By the way, I installed the apple router and that has been fantastic!  Thanks
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Sounds like the computer is being pretty difficult in trying to get this upgrade installed. There is another way. We can use another computer to install 10.6 to the target computer by using something called target disc mode. It’s not a common practice so you may need a little assistance. I would be happy to take care of it for you if you prefer. Be sure you’ve backed your data up prior to me coming if you need. If you’d rather have the instructions and do it yourself, you’ll need another mac and firewire cable to do it. I can provide instructions if you need. Just let me know if you feel I can help.