Please provide information about your computer, this includes is it a notebook or desktop, is it a custom build or brand name such as Dell or HP, if it is provide the model name or series number (not serial) providing these details will enable us to better assist you.
syslinux is a bootloader for Linux platforms, you may have installed this to the C: drive by accident.
Check the Boot Sequence in the BIOS again;
Reboot the system and at the first post screen (where it is counting up memory) start tapping the appropriate button that allows you to access the BIOS (esc - Del – F2 etc)
This will enter you into the BIOS/CMOS
Find the Advanced area and click Enter
Look for Boot Sequence or Boot Options and highlight that click Enter
Now highlight the first drive and follow the directions on the bottom of the screen on how to modify it and change it to DVD/ CD drive
Change the second drive to the C or Main Drive
Once that is done then click F10 to Save and Exit
You will prompted to enter Y to verify Save and Exit.
Click Y and the system will now reboot with the new settings.
Let us know if this is how the boot sequence looked when you just checked or if it had changed.