RECOVERY (D:) Necessary?

I have recently purchased a Dell Inspiron 1520 with 32-bit Vista Home Premium and an 80GB hard drive. I went to check out my partitions, and I have a 110MB "Healthy (EISA Configuration)", 2.50GB "Healthy (Primary Partition", my 61.92GB OS (C: ) drive, and, unexpectedly, a 10.00GB RECOVERY (D: ) drive. What does that last partition (my D: drive) do? I've heard that it can be used to restore my system to factory settings, but I haven't seen any reference to it in the Control Panel or Microsoft's help pages. If I don't need it, or if I'm using system restore for my C: drive, can I just clear the D: partition and install Ubuntu on it or something? I have already copied all of its contents (folders: 2.98GB Dell, 6.63MB Program files, sources, Tools, Users, and 809MB Windows) to an external hard drive, just in case.
Any enlightenment on the purpose and necessity of any of these non-C: drive partitions would be greatly appreciated.

 

You should keep it you can access it @ boot to restore your computer to factory settings.
EDIT: Most of the time it is hidden but, there are ways to access it within Windows *supposedly* http://www.google.com it.

 

What if I copy the exact contents of the D: partition onto my external hard drive? Then if something goes wrong, I can copy it back, and then access it at boot, right? I'm just wondering what the implications of deleting it are.

 

I'd just call Dell & ask for recovery Disc(s).
They should be glad to give them to you for free.
Then you'd be in a situation where you can delete it.
But note: it's hidden you can't access it to copy the contents

 

It is hidden? That's weird... I just hit Windows + E, double click on the RECOVERY (D: ) HDD icon, and I can access it just like any other folder or partition - I already have a copy of it on my external. Are you describing something different, or have I somehow changed settings that made it unhidden?

 

Sometimes(most) its hidden.