Messed up bootloader, can no longer boot computer with CD in drive

Question

I'm trying to dual boot Arch Linux and Windows 8.1, on a Lenovo Y580 that already has Windows on it. I went through the whole installation mostly following the Beginner's Guide, picked the Syslinux bootloader and tried to set it to chainload Windows, everything seemed to go smoothly. When I restarted the computer, it just skipped straight to Windows. I figured I must have messed up the bootloader so I put the live CD back in to try to fix it, but now nothing will boot while a CD is in the drive. It hangs at the Lenovo splash screen; I can't get to the boot menu, I can't get to the BIOS, I can't do anything. When I take the CD out and restart it boots into Windows.
Presumably I messed up setting the boot flag, or something? I have absolutely no idea how to diagnose this problem, I don't even know how to investigate it because I can't boot anything besides Windows. Please let me know if you need more information, I wasn't really sure what details would be relevant to this issue.

Answer 1

What is odd is that the system reacts to a CD being in the device (i.e. it doesn't boot Windows while it does if there is no CD in the device). This is why I think that the boot order is probably fine. Nevertheless, I don't see why it wouldn't boot the Arch CD. I could imaging some potential reasons none of which is either likely or common or easy to resolve.
(So for now, the interesting questions about that would be:
1. How did you get the Computer to boot from the Arch CD when you tried to install Arch? Did you just reboot with the CD in the drive or did you do anything specific with your Windows and/or BIOS first; if so, what?
2. If you put another CD (say, your favorite audio CD) into the drive, does it still hang at the Lenovo splash screen? Normal behavior would be that it just boots Windows.
3. Following henk's advise and checking the boot sequence in the BIOS, what exactly do you see, what is the exact boot sequence?)
burkaman wrote:Is there any other way to get to my stranded Arch installation
Sure. Just none that would be easier than from the Arch CD. You could for instance write the Arch ISO to a USB flash memory and boot from USB, like so: https://wiki.archlinux.org/index.php/US … In_Windows
If your problems booting from CD persist, this might be worth a try. (However, you will still have to make sure that your boot order lists USB before the hard drive.)
burkaman wrote:maybe change the boot flags some other way?
Sure. But it is
(1) overwhelmingly unlikely that your problem with Arch has anything to do with boot flags and
(2) without a deeper understanding of how partition tables are designed and how disk partitioning utilities work, you are much more likely to seriously damage your other (Windows) partition(s) than to fix your Arch Linux partition(s).
If you feel compelled to try nevertheless, have a look at wikipedia's list of disk partitioning software: https://en.wikipedia.org/wiki/List_of_d … g_software
One more thought on your Arch installation and its non-working bootloader: If you by any chance set the default boot option to Windows and the timeout to 0 the behavior you describe (booting Windows instead of showing the bootloader) would be the expected one. If not, the bootloader has not been installed to the harddisk since the bootsector is obviously still occupied by Windows' own bootloader. (Otherwise, there would be no way for Windows to boot.)
Last edited by gay (2014-06-02 15:47:18)