So, I was trying to do two things at once and it went badly:
I was just setting up a new HDD with Window7 on it, next to an old HDD with windows xp on it. I decided to shrink the XP drive and split it into tooto give both OS access to a common empty drive rather than have them accessing each others main partition. During the shrink process I disabled the Virtual disk manager which caused: "virtual disk manager the service cannot be started".
Now I have a 500Gb drive of which only 120 Gb is accessible. Disk management and EaseUs say the partition spans the whole drive and so I can't re-extend it. I really don't want to format the drive but I need access to the other 380 Gb!
Thanks for the advice but unfortunately it had no effect. I used both Win7s own Defrag and Defraggler (which is a nice piece of software by the way!) to no effect. MyComputer still thinks the drive is a 120 Gb drive and Computer management thinks it is a 500 Gb
You might use TestDisk by Grenier to see if it recognises the disk spaces correctly. If it does then you can rewrite the MBR with that information. Its Deep Search might pick up the correct boundary.
If not, then a tool like PTedit32 may be the one to use. For me, it does not do a great job of finding partition boundaries, but you can use it to write them in.... just learn a bit about the rules first, and then put the first boundary where you think it should be.
If it all blows up, I don wanna know.
TestDisk has a good help site. You might [should!!] backup your partiton tables first. Plenty of tools will do that. Use TestDisk to check your backup MBR tables, too. They may not be corrupted.
Don't try to run more than one partition tool at a time, including Window's Disk Mgmt console. They interfere.
I played with this on a rainy night. On a test hdd I installed W7 to a new 20GB partition, then used PTEdit to shrink the partition to 18GB [40960000 sectors down to 35156250], setting the total NTFS sector field in the boot sector table to one less, 35356249, writing that, and writing the partition table mod. It booted fine, but TestDisk reported that the head value was now 240 and not 255 as before. PTEdit says it is 255. I'll try to resolve that.
Of course, for your problem, there is a free disk image tool available which does data and not sector copying - if you have space on another hdd that might be your safest solution. Image, perhaps shrink, delete original partition, reimage. Fdisk would clean the confused hdd if necessary.