okay,
shows me that this /mnt/windows is mounted as fat32, and is on the fifth partition of the second hard drive, yes? (hd
b5) so i have not got a clue where your G: partition will be physically, if that's where your C: partition is!
try typing "ls -al /dev/hd*" to see what choices you have, then mount each one and see what's in it, until you find out which one you are looking for.
Read this too, You need to recompile the kernel to add support for NTFS filesystems. Careful because NTFS support in linux is a lot more unstable than fat32 support, and the ability to write to a file is not guaranteed, while reading files is more or less okay, or so i have heard.
Recompiling the kernel is pretty easy, as it says, you should run either xconfig, menuconfig, or config. You will prefer xconfig i think, i have not used it, having used menuconfig which is pretty easy. It's a program that recompiles your kernel for you using a GUI, either point and click or menu based, depending on which program you are running, you then save the new kernel (don't overwrite your old one!) and when you boot up, use the new kernel and you should have ntfs support, so long as you added it when you recompiled. To boot into your new kernel, you might have to run whatever bootmanager program you use and add the new kernel to it. (lilo, or grub per example, i have not used grub, so master of reality, voidmain or somebody else would have to help you if you had questions about that)
Now, back to that fstab line, i think you need to read 'man mount' and 'man fstab' to know all the other options, i think you can just replace vfat with ntfs, but i have not done it, so best check the man pages before you go ahead. You might, as i say, want to change some of the other options too, the info required can be found in the same man page, but get it working before you do that.