Burned CD from iso file, but it won't boot. Wish to run it first & then install. Would appreciate suggestions.

It would appear likely that your download has been corrupted during the download procedure if the md5sums do not match.
Before you delete the data, make sure you have the correct md5sums for the file you downloaded.

Also, make sure you downloaded a release which is compatible with your system (32bit or 64bit).

If the sums still do not match, you will need to redownload Kubuntu unfortunately.
If the sums now match, try erasing your disc and trying again, at a slower burn rate. Bad burns do occasionally occur.