How many partitions do you have? Your Vista partition might not be set to active...just a thought.
In this case:
Boot again with the Vista cd and go into the command prompt.There, type:
diskpart <enter>
diskpart>
List disk
You will get something like:
Code:
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 250 GB 0 B
diskpart>
select disk 0 (or your disk number)
diskpart>
list partition
If you have more than 1 partitions, you will get something like :
Code:
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 GB 0 MB
Partition 2 Primary 150 GB 100 GB
diskpart>
select partition 1
"Partition 1 is now the selected partition."
diskpart>
active
diskpart>
exit
REBOOT.
Repeat with the other partition if it doesn't work.Might help.