I had a problem that got solved and I wanted to make a note of that here because my searches brought me here to look for answers.
On WinXP SP3 I had problems with an external usb hard drive and its two extended partitions. When I plugged the hard drive in, the primary partition came up and was accessible. Two extended partitions also showed up, but were not accessible and XP suggested I format them. I got my data back using the Partition Recovery function of the EaseUS Data Recovery program.
At first I tried Partition Table Doctor 3.5 and Fixboot on the partitions. PTD and XP disk management showed both partitions, but the sizes didn't seem quite correct (and weren't). After running Fixboot it said it couldn't fix the partitions and suggested I try their EaseUS Data Recovery. Also, PTD suggested the file system on both partitions would be Win95/Fat32, though I remembered it to be NTFS, and setting it to NTFS in PTD and running Fixboot again didn't solve it.
I tried the Data Recovery program and ran the Complete Recovery function several times, which seemed to match the problem I had ("disk displayed as RAW or Windows asks Do you want to format this drive?"). Unfortunately it twice hung about half way through processing the first partition, after finding about 18000 files. I tried recovering those files from the progress the program had made before hanging because it allowed that, but found that most of the files and all of the directories it had found seemed bogus, like the bulk of the stuff in about 300 50mb archives.
Anyway, I'm glad I tried the Partition Recovery function after that, because it found two NTFS partitions with partition names and everything intact and I got the data back. It was a bit odd in that the hard drive came from a working XP-installation on a laptop that to all appearances had a good hard drive and an intact file system, only the laptop display broke. I don't know why or how those two partitions got "deleted" or dropped when I plugged the drive in as an external usb drive, because I didn't touch them. Hope this helps!
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