Help-Error Msg-"Last Backup Failed"

I have a new Dell Studio 1555 (Vista 64 no hardware upgrades)and I tried to automatically back up my files with Vistas built in utility. When I ran it for the first time it suggested to make a complete full backup so I checked OK, now I get an error message every time I log in that says "The Last Backup Failed" and it also says "Your D drive is running low on space" I have 36 programs on the D drive now. Just for funsies I tried removing the ADAware program from what I thought would just be the D drive but it completely removed it from my computer. Now I'm wondering if I ever delete any more programs from the D drive that are crutial to my operating system I'll be in "Puter Hell"
I was going to try the format but didn't want to wipe my whole system out.
I'm really a "simple" plug and play guy and need an easy way to use the D drive back up. All I really wanted to do was backup my family pictures and music...if that's even what the D drive does...I dunno. I tried to find a way just to increase the size of the D drive but couldn't find a way. Is this D drive, named "recovery", crutial in case my system takes a nose drive. Thanks everyone in advance!

 

Do you mean the D partition and it is the recovery partition of your notebook?

If so how did you access it before to install software? Since this is a hidden partition to be used only in case of system recovery.