Try a smaller download
Go to the following link
http://puppylinux.org/main/Download%20Latest%20Release.htmClick on one of the links pertaining to
lupu-525.isoSave this file to your desktop
Note: it's 130mb in size, so if you have a slow connection, it will take some time
After downloading, can you burn that Image file to a blank cdrw or cd
Ensure to burn as an IMAGE file
insert the CD into the Computer that won't boot
Restart the computer, follow the prompts, the computer should boot to Puppy linux desktop
If you have an External USB flashdrive you can backup important files/folders too
Plug it into your computer
Mostly everything you need to do will just involve single clicking
Open sdc1 by single clicking on it>>I assume that is your external USB drive, leave this window open
Hover over the bottom left drives, check to see which you have your files on
You can tell by the size of the disk when you hover over it
Your C: drive may be indicated by eg... sda1 or sda2
sda1 may be your recovery partition, look for your C: partition with all your files you want to backup
Let me know how that goes