I'm able to access my USB-drive (from which I'm running MEPIS right now) and my C-drive which has all my Windowsy stuff on it.

I tried putting the (bad burn of a) CD-R into the drive and it was also recognized, but when I put a blank DVD-RW into the drive, nothing happens, and when I try to create a device-link, it tells me that medium does not exist.

I still want to do backups before I do a hard install. How do I burn discs from Mepis?

I find when running a Live CD (on most distros), the CD is locked for use with only the Live CD. You could probably accomplish the task using the Partition Magic Live CD, because it loads itself into memory, and your allowed to remove the cd after you log in.

I seem to remember both SLAX and Ubuntu both had an option to load the contents of the live cd into memory so you could use the cd drive for other tasks to include burning of a cd.

You should find this option under a boot menu as mepis boots.

I am re-editing this post. I assume you wanted to burn an iso image using a livecd. After reading your first post again, I see you wanted to burn a data CD or DVD to backup your hard drive. Below I listed what you need to do.

When you boot SimplyMepis from a livecd or USB stick, you will see a list of boot options. You will notice there is no option to load to ram from the menu.

But it can be done, I know, I tried it last week. Type

It will echo at the boot prompt below as you type.
And hit enter key.

After it loads to ram, it will run faster. BTW, k3b is available. All you have to do is remove the livecd. put a blank disc, open k3b and create the type of disc you want.

Hope this helps.

Because of your poor choice of thread title, I think those replying to your question missed the key detail (IIUC) that you are booted on a USB memory stick, not on a CD.

So your question is not the usual: how to get the liveCD out of the way in order to use the CD drive for other purposes.

Your question is which preinstalled programs to use in Mepis to copy data from a Windows partition to a writable DVD, and how to use those programs.

I didn't happen to know the answer to that, but "k3b" suggested in the previous post looks like a good suggestion of at least what documentation you want to look at.

At first, it seems I misread the post again, but I was giving Koyae and other readers of this post how to load the image to ram in case some of them were using Livecds and wanted to free up the cd/dvd drive.

I prefer loading images to ram, it runs much faster.