Can a failing hard drive mess with booting from a CD?

TL;DR below, though the text explains the problem more specifically.

Recently I had to troubleshoot my brother's computer as it would not boot up anymore; even safe mode would hang at loading files. We ran a start-up repair and after 2 hours it didn't work so we decided (like we usually do when booting up becomes a problem) to boot from the installation CD and reformat the drive.

This is where things got strange; upon booting it would load the windows files like normal, then show the windows logo. After that it goes to a black screen with a cursor... and stays on that screen for 5 or so minutes (much longer than it should be) until finally popping up to the start up screen (sometimes it would not pop up). We then hit the "Install Now" button and it goes to the "Setup is Starting" screen. Once here it just hangs (though the cursor is spinning); we waited about 15 minutes before shutting down.

At first I thought maybe the disc can't be read correctly, so after trying my other disc and even an external disc drive (thinking his internal one is shot), I still had the same problems. So as a last attempt I unplugged the problem HDD and booted from the CD; black screen lasted less than a minute and upon clicking "Install Now" the setup screen showed up for a few seconds and then it finally proceeded to the rest of the installation. I now know the HDD is obviously gone so I bought a new one and Windows 7 is currently installing as I type this, but my question is why would the hard drive make booting from the CD impossible, and I haven't even got to the part where I choose which drive to format? I have fixed a few computers and did plenty of installs and this was the first time where it was the HDD preventing me from even being able to reformat it.

TL;DR - How can a hard drive prevent me from booting from a CD when I haven't got to the part to choose a drive to format?

Thanks in advanced!

P.S. I wasn't sure if this was the correct sub-forum, but it had something to do with the installation disc. Sorry if I posted in the wrong place.

I have similar issue as well. Not only booting from HDD give me diskread error message, when I booted from external USB drive to reinstall my Windows, the "Setup is Starting" screen hangs for a few hours. I tried to check my disk status via diskpart, it hangs after I executed diskpart command. I tried several suggestions with bootrec.exe/fixmbr and fixboot, but then it hangs at bootrec.exe/scanOS and/or bootrec.exe/rebuildBCD.

My theory is, the installation screen will freeze when it is trying to detect which hard drive in the PC to install the Windows into, in case your hard drive is failing. Same problem with diskpart command, I think it freezes because of trying to detect a failing hard drive. Booting from CD/DVD and/or external USB drive works normally, only the part when it is trying to detect your failing internal hard drive it will hang.

If replacing a new HDD solves your problem, then I guess I have to replace mine too.

The answer is yes. Bad code on the HD can block the PC from booting at all. To test this unplug the HD to see if a disk will boot and run. You can use a Linux disk to test hardware or the boot disks from Troubleshooting Windows 7 Failure to Start .

If so slave the HD to another PC to run Disk Check and HD Diagnostic. But this may not resolve the problem which sometimes requires rescuiing your files off of it to wipe it with Diskpart Clean Command.

The reason it will still allow the other PC to start is because it isn't set first HDD to boot so doesn't interfere by being queried. However it's conceivable that it could block both PC's from booting so as a last resort you can try a self-booting disk like Paragon Rescue Kit Free Edition 11.0 Free to rescue files followed by Partition Wizard bootable CD to Quick Wipe the HD.