Disk Read Error Occurred

So my mom has had this computer since 2003. It's a POS but she loves it, and she wants me to fix it, but I've run into a problem I can't seem to fix.

Initially on boot up, I received too errors. One was an easy fix, I just had to replace the BIOS battery.

The second is:
"A Disk Read Error Occured
Press CTRL+ALT+DEL to Restart"

I went to my parents house and got the original boot up CDs to boot from CD, but when I went to the Boot Up option screen, Boot from CD is not an option o.o!

So I went into System Setup under Boot Sequence and saw that CD-ROM device is not installed.

I've tried every boot option available.
Normal, Diskette Drive, Hard-Disk Drive C:/, Boot to Partition, Safe-Mode
Each time I receive the same message:
A disk read error occurred, press CAD

I've also tried to CTRL+F11 to reinstall the OS at the Dell Screen, but that doesn't work either

I'm at a loss
I hate Dell and this is the many reasons why, but momma loves her crappy machine, so I'm going to be a good daughter and try to fix it ^^

Some advice would be awesome, please an thank you