Uninstall 10.10

You can just delete the partitions that Ubuntu is instal;led on (This will destroy the data stored so ensure you have backed-up what you need). You can then do a clean install to the free space.

Thanks actionparsnip, that solved my question.

Ooops... no it didn't.
Now I can't boot Win7. After screen says "Loading System", i get

error: no such device: ac86ad78-b810-4417-941b-3c0f6e6743db.
grub rescue>

Where do I go from here? Win 7 was loading from the c:\ drive.

You'll need to reinstate the Windows bootloader using your windows CD or supergrub

Any chance you could expand on that?
My Windows CD loads Windows to where I have the desktop background and a mouse pointer, but nothing else - just hangs.
I tried to re-install Ubuntu 10.10, but in the Where Are You window, it loads maybe 75% of the files, then says down at the thermometer:
"Ready when you are..."
and the Forward button stays greyed out.
Ready for what? What's the response?
Could I run supergrub from the CD without fully instaling 10.10?
And where are the instructions for supergrub?
It appears to me that 10.10 screwed up my drive table or boot record (BCD) or something.

AT least I can run Win 7 again. I found
bootrec.exe /fixboot and
bootrec.exe /fixmbr
Still can't install 10.10.
On the Who Are You (not Where Are You) screen, the files load about 80%, then it goes to "Ready When You Are..."
Hunh?? Ready for what? No apparent response is available. "Forward" button is greyed out.
Oh well.

Tried another flavor - didn't like that.
Re-installed 10.10 off mem stick a couple times.
Re-formated the one HDD numerous times. Finally got 10.10 going, and I LOVE IT.
Thanks, you guys. I'll be running under Ubuntu 10.10 most of the time.
All the time, if I can get Quicken for Linux.

Thanks marcus aurelius, that solved my question.