|I have a computer with both Vista and XP installed on it. I installed Vista's Windows on the second partition on a drive, after I installed XP on the first partition on the same drive - the drive had two other partitions at the time that had been software partitioned (using XP's NTFS) and formatted in XP. XP sees it's Windows partition (the one Windows was installed on) as C when XP is booted; Vista sees it's Windows partition as C when Vista is booted. |
(I used Vista's dual boot feature at first. When I discovered that ALL the Vista System Restore restore points are deleted in Vista EVERY TIME you boot XP, I installed a third party boot manager program (BootIt! NG), set it up such that Vista's restore points would not be deleted, and I have used that to dual boot with since.)
I suspect Vista sees it's first installation of Windows as being on C, no matter which hard drive, or partition on a hard drive, you install the Windows partition on, and regardless of whether other partitions have already been assigned drive letters when Setup is run. The same probably applies to Windows 7.
XP and 2000 will assign a drive letter other than C to it's Windows installation (the partition Windows is installed on) if Setup detects other hard drive partitions have already been assigned drive letters when Setup is run.
Make sure there are no USB flash drives or USB connected external drives plugged in while booting. Under some circumstances, the bios may try to boot from a USB connected device - you either get "no operating system found" or similar if the drive is not bootable (flash drives are not bootable unless you make them bootable) , or a STOP error message (you can't boot 2000 and up from an external drive), or the boot will stall. The bios will probably not try to boot anything else.
If the computer has a floppy drive, make sure there is no floppy disk inserted in it while booting. If the floppy drive is before (above) the hard drive in the boot order in the bios, you will get "no operating system found" or similar if the floppy idisk is not bootable, and the bios will NOT try to boot anything else.
Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)
The same thing applies for the SATA power connection.
If the bootable SATA hard drive is connected to a SATA drive controller card in a mboard slot, the boot order in the bios must be set to boot from SCSI, rather than a hard drive. E.g. Floppy drive ,if one is installed, then CD drive or similar, then SCSI.
If there are any IDE drives, including optical (CD or DVD) drives....
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittent, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.
Try another data cable if in doubt.
You may have jostled something while you were fiddling around in the case.
You may have un-intentionally bumped the ram and made it's connection in it's slots poor. Make sure it's all the way down in it's slots, and that the latches at both ends of the slots are against the ends of the modules.
Make sure all wiring connections inside the case are all the way into their pins / into their sockets.
Make sure all cards on slots are all the way down in their slots.
Does the computer also have an IDE hard drive ?
Some bioses default to try booting from an IDE drive first; some default to try booting from a SATA drive first.
If the computer has both an IDE and a SATA hard drive, if the IDE hard drive is not bootable, if the bios is trying to boot from it, you will get "no operating system found" or similar . The bios will NOT try to boot from other hard drives if the first one it tries to boot from is not bootable.
In that case, look for either of these in the bios
- a list of hard drives - it's often near the boot order settings - the model of the drive you want to boot from must be listed first
- less likely - model numbers of hard drives, or HDD0, HHD1, etc., or similar, in the boot order list - the drive you want to boot from must be listed first.
Similar applies if you have more than one IDE hard drive or more than one SATA hard drive. If the bios defaults to try booting from a non-bootable drive, you will need to change which drive it boots from in the bios (or change the jumpers on the IDE drives, or switch which mboard header the bootable SATA drive is plugged into).