Have the same problem.
New HP i5 Pavilion laptop, 500G hard drive, Windows 7. Want a dual boot, so here's my story!
First, put Ubuntu 10.10 64 bit onto the USB stick, works fine.
Then Win 7 full Disk Defrag.
Now Shrink the Win7 C drive:
Control Panel > Admin Tools > Computer Mgmt > Storage > Disk Mgmt.
It offered to shrink it by about half, so Win7 would be on 237GB; accepted.
It now lists the following for the disk:
System 199 MB ntfs
(C) 232.01 GB ntfs
Unallocated 209.79 GB
Recovery (D) 23.66 GB ntfs
HP_Tools 103 MB FAT32
So now have a huge ~209 GB available for the Ubuntu install.
Rebooted Windows a few times, make sure all is OK, and changed the bios so the USB stick has priority.
Re-started booting from USB into Ubuntu, works great, can access the internet.
Install button. “Erase and use the entire disk” obviously not the choice.
There is only one option: “Specify partitions manually (advanced)”
Up comes the “Allocate Drive Space” screen, which lists:
/dev/sda1 ntfs 208 MB 69 MB
/dev/sda2 ntfs 249123 MB 47521 MB
unusable 225260 MB
/dev/sda3 ntfs 25404 MB 21687MB
/dev/sda4 fat32 108 MB 33 MB
Its different sizes from what Microsoft Win7 reported, but have to assume close enough. When I click on “unusable” which is the new unallocated space on the harddrive, the only option available is “Revert”. The other 4 options are there but not accessible: New Partition Table, Add, Change, Delete.
Do I really want to hit that Revert button? No, don’t think so; stuck.
There is also a graphical format showing the same entries as the table except that instead of “unusable” it is called “Free Space” with 225.3 GB.
So cannot do the dual-boot installation.
sda4 appears the candidate for deletion, HP Tools, but does that affect running Windows?
If I delete sda4 then will the unusable/ "Free Space" become available and the "New Partition Table" button become workable?
Should I delete this sda4 using the Win7 tools for Disk Management (and not the linux tool)?
Will Win7 agree to let me delete sda4 or maybe its protected by the manufacturer HP?
Anybody have experience with this on HP?
Thanks, appreciate your insight.