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#21
It may be a hardware issue, It may also be a problem with the partitions ( volume drivers ) attempting to share resources.
If the latter is the case, it should be possible to fix by booting GParted livecd - deleting the C partition , recreating it ( slightly smaller than the original).
Exit Gparted, boot 7 dvd and install on that new partition.
If the other partitions were recognised - they should be fine.
If, when booting Gparted, the drive is shown as Raw:
Again click New at the top of the Gparted UI and create a new ntfs partition - again smaller than the original C ( do not overlap where the previous partitions, if any, were).
To avoid the 100mb partition - mark it Active (rt click it select Flag On , Apply).
Install 7 to that new partition - d/l the free Partition Wizard - select partition undelete - do a Quick search of Unallocated space.
Tick the Partitions to keep ( include the one you just created.)
Download GParted from SourceForge.net
BEST FREE Partition Manager for Windows supports all 32-bit & 64 bit Windows No-server OS.