Yep that's what I thought...your D: drive is just a partition on your C: drive where Dell has a bunch of their propietary stuff mixed in with some backup Windows files.
I suspect (if memory serves me right) that you simply can delete that stuff...but it's been so long since I've used WIndows 98 that I can't remember...it may depend on what all Dell has on there...Compaq did that to me and stuck all their factory image garbage on there.
I really don't want to give you a "bum steer" especially if there is something important on there, but I really think that you can get rid of it...I do know that you can use the D: drive for extra storage (just create a folder in there and put stuff like files in it).
My honest recommendation is to go buy a nice big hard drive and transfer everything on to it, and then when you buy your new computer just move your new drive over to it.
But yeah, your D: drive is simply a save partition on your C: drive (Windows just reads it as a seperate drive because of the partition)...in it you should find both backup stuff from Dell & Windows.
You might want to post in the Software Help Forum
, I'm sure one of the guys in there (bunch of them are professional tech support) can confirm this.
I seem to remember someone that not only formated that partition but remerged it back with C: and Windows wasn't to happy about that.