The 0xC05 stop error is fairly common when installing Windows Vista and is usually attributed to a defective installation CD, old BIOS configurations or problems with hardware.
Look at the following steps for possible solutions to this problem.
1) Check that your drives are working (the lights are flashing) and you have put the right media-type in the right reader (DVD’s can’t be read by a CD drive).
2) The Installation CD might be damaged. If it repeatedly stops working take the CD out and gently wipe it with a damp cloth. Check it for scratches or similar damage. You can ask for a replacement CD if you believe that it is damaged.
3) As mentioned this error is often a BIOS problem. Go into your BIOS at start-up (usually press the DEL key); check the computer’s documentation as this procedure differs depending on the machine. Make sure you have both your drives enabled and one enabled as a start-up device.
4) You can try setting the drive with the CD inserted to IDE mode. Again, access the BIOS right from the start-up screen, and look for your devices and peripherals. Remember to set it back to SATA mode if installation is successful.
5) Try to update the firmware of your drive. Check the model and go to the manufacturer’s site; they will usually have the latest updates for download at the site.
6) Insert a different CD to determine whether your DVD or CD drive may be the problem (wrong connection or a genuine hardware problem). If you have the option to try more than one disc and they read fine, you may have a problem with a defective installation disc. You can also try to read the Vista disc from a different drive, should one be available.
7) Sometimes this stop error is due to a bad RAM stick inserted on the motherboard. RAM is a frequent cause of many stop errors and the only way to check is to open up your case and take out one RAM stick at a time. If you have another computer try to place the RAM there and see if it works. You can also run the following memory test to determine any faults: Windows memory diagnostic
8) Update your BIOS in case you have an outdated version for your motherboard. This can cause problems with hardware devices and result in poor performance and stop errors.
Lastly, if everything fails disconnect all devices (zip-drives, USB devices such as cameras etc.) leaving only the mouse and keyboard. Then try the installation process again.