Windows 10: I installed Win10 and now my previous Win7 drive won't boot. What could have happened?

I'm familiar with the bios and setting boot order. I replaced the SATA cable and used a different power cable but that couldn't have been it because the drive is recognized in the bios. I just get the dreaded blinking cursor in the upper left hand corner of a black screen of opaqueness. I did it over and over and once got NTLDR is missing then back to the flashing cursor. In Disk Management it says:Win7 drive not booting: Healthy Basic Data PartitionWin10 drive working fine: Healthy Boot, Crash Dump, Basic Data PartitionI just noticed there is also a 519mb partition on the Win10 driv

:)

 

WIN10 /WIN7 Dual boot, WIN7 forced to upgrade to win10, now I can only boot to Primary WIN10 drive

I have a WIN10 install on a 256 SSD (DRIVE 2)

and had a win7 install on a 1tb WD Black HD (DRIVE 5)

My primary boot was WIN10 (D2) and always had the option of picking wich drive to boot to on start up.

I was recently forced to upgrade my WIN7 (D5) to WIN 10. It completed the update and I was using the opperating system on my 1 tb HD and it was working fine. Then I shut off the computer and came back about 4 days later and I couldnt boot to my second
win10 install. (there may have been an update to the win10 before I shut it down)

I went into boot up options and selected the 2nd win10(win7) Drive 5 as primary boot and it reverted back to the original win 10(drive 2) boot.

What is the best way to have a dual boot win10 system and how can I change my boot up options so that I can continue to choose the boot up drive?

WIthout a doubt the upgrade Win7 drive is still there and can be used, but there must be a boot settings that is preventing it from being accessed.

If i am not allowed to have a dual boot WIN10/Win10 machine, can I revert back to WIN7 on the upgraded drive?

Also, original WIN10 install was from a win8 upgrade, 2nd one is from a win7 upgrade, both fully registered versions of WINdows.

Much apprecaited

 

Win10 clean install on new drive, dual boot w/win7 on old drive. New Win10 drive won't boot

As per subject line above, I did clean install of Win 10 on new drive. Left Win7 on old drive. All went fine; PC boots as long as old drive is present. Boot option screen appears at boot offering choice of Win10 or 7. Works fine. BUT, when I removed old
drive with Win7, system won't boot from new drive (C. Apparently Win10 installed boot selection and/or something critical on the OLD drive. The new drive shows the Win10 logo in File Explorer (when old drive is present), and all Win10 files appear to have
installed correctly on the new disk. But it won't boot by itself - so something is missing. (Yes, I changed the boot sequence order in the bios to look for the new drive.) But bios prompts for a bootable disk, meaning the new C: drive is "not bootable". What
gives?

Thanks for any help!!!

 

Dual Boot Win7 & Win10

Here are my steps for dual booting:

• Create a system image - store it on an external drive
  
  
• Disconnect from the Internet and stay disconnected - part of the install asks about connecting
  - do NOT connect just yet.
  
  
• Create the space for the 2nd OS.
  This is tricky - drives initialized as MBR can only have 4 partitions (an extended partition allows for more),
  many OEMs create 4 primary parts and you have to adjust their disk schema.
  
  Post a Disk Management screen shotClose the left and right panes
  The columns should also be stretched to clearly show the values, most important is the Status column
  If you have many drives, you might have to adjust the middle separator and drag the bottom edge of the window down to show the maximum information.
  Then in the View menu, pick Top and change it to disk list - no need to post a pic - just note the initialized format (MBR | GPT) and post the information.
  
• Unless the 2nd OS will be used on a daily basis, keep the space to a minimum.
  Win10 + pgms on my machine takes up about 15 GB.
  I don't use Win10TP as my main OS - that's Win8.1, so data isn't a concern.
  30 - 50 GB is more than sufficient.
  
  
• Once the space is available - take your time here - there are traps with MBR disks.
  If your disk is initialized GPT, no problem - easy! But... MBR - make sure you know what you're doing.
  Just free up enough unallocated space,
  -> do not create a partition and do not format the space.
  
  
• When you're ready to install Win10, use a disc to avoid EFI issues.
  
  1. Boot to the Win10 install disc (see your machine documentation on accessing the Boot Order menu at startup)
     
     +editA
     These steps are probably NOT necessary, it was an afterthought when I installed Win10 the 3rd time as a dual boot to Vista. That is when I noticed the Win10 page file on my Vista boot drive - which caused Vista a bit of a problem (temporary page file created - yada, yada, yada) - I recreated the Win10 page file on it's own partition and then reallocated the Vista page file for good measure.
     
     At the first Win10 install screen, Press Shift+F10
     Then enter these commands in the Console window
     
     ^^ denotes comment, not a command
     Launch Diskpart
     lis vol
     
     ^^ remove the drive letters from all drives
     ^^ it's easier if you disconnect external drives that aren't needed for this exercise.
     
     sel vol #
     remove letter=
     ^^ specify the letter that was shown for that volume in the lis vol command
     ^^ repeat this (select volume, remove letter=) until there are no volumes with letters shown in lis vol
     lis vol
     exit
     close the Command prompt with the X in the upper right hand corner
     
     You should be back in the Win10 install now.-editA
     
     
  2. Answer the questions as if you were doing a clean installation (language, region, etc)
     
     
  3. Choose a custom install
     When it asks you where you want to install, choose the unallocated space
     Let the install complete, the rest should be easy.

+editB
When Win10 boots up, you shouldn't see any other drives - this is good.
Configure the volumes for each OS - I suggest that you keep the two OSes separate, only expose the volumes you need to for each OS. Your Win7 should see everything except the Win10 volumes. Your Win10 should only see volumes you'll use in testing (i.e. what ever you create on the currently new and blank SSD).
If you need data from your existing Win7 install, it's probably better to copy what you need than to expose your good data to Tech Preview code.
-editB

When Win7 boots up, you will see the Win10 drive - remove the letter from that drive. Keep your system separate.

If at any step above you need some help, please ask ... you might have to wait, please wait. The hardest thing to do is wait and the easiest thing to do is "ooops, but I thought you meant...."

I think I remembered all of the steps I took - but... I'm human too *Wink