One of the most stupid things Canon does is to make updating their RAW processing software, Digital Photo Professional, dependent upon having a prior version installed.
Computers crash and need to be reconfigured. People change computers. That happened to me last year. Yesterday I simply decided to do an upgrade and my anti-virus software scrambled it for me and I had to uninstall the mess it left me. Thanks, Avast! I was left without the old or new version of DPP and I was back to square one.
The Canon software is designed for use by people who bought Canon cameras and use Canon RAW files, so why all the nonsense? Why not just make the software available to all users? Why the obstacles?
While I am at it, why does the software not automatically advise the user when a new version becomes available?
I have no idea where my original version of DPP is and I couldn't see it on my original Canon installation discs. Both times I went looking on the interweb and found various solutions which involved updating the Windows registry - feasible but a last resort for me.
However, both times I eventually stumbled on the ideal solution which worked!
1. Download DPP v1.0.0 from this location.
2. Install it (and don't worry whether it works or not).
3. Locate the latest DPP upgrade version from the Canon site, by inputting your camera model number and selecting "downloads" - in my case for the 60D I reached this DPP upgrade page for Mac and this DPP upgrade page for Windows.
4. Download it.
5. Install it.
This procedure worked for me on Windows 8.0 and 8.1 and presumably would work on any Windows version. My compliments to the originator of this solution at www.hugolim.com.
Finally, copy and store the DPP v1.0.0 installer in more than one safe place, just in case it is needed again!