How to solve basic Dual Boot Issues

Case 1: You have Dual Boot Win7 and XP/Vista and you lost the XP/Vista boot option at startup, but Win7 boots fine.

Solution:
1. Start Win7.

2. If you can see your XP/Vista partition in Computer, write down the drive letter (e.g. D

3. If you can't see the XP partition and you see all others but this one, open Control Panel - Adminstrative Tools - Computer Management -> Disk Management(left pane) and right-click the partition without a drive letter, choose "Change drive letters and paths" and assign a drive letter for the partition, e.g. D: .

4. Open an elevated command prompt and type the following lines followed by Enter for each line, changing the drive letter D: (in blue) with the one on your XP/Vista partition:

FOR RESTORING XP


bcdedit /create {ntldr} /d "Windows XP"

bcdedit /set {ntldr} device partition=D:

bcdedit /set {ntldr} path \ntldr

bcdedit /displayorder {ntldr} /addlast


FOR RESTORING VISTA

bcdedit /copy {current} /d "Windows Vista"

(You will get a response saying that a new {UUID} was created successfully.
Write down or copy the new UUID.)

bcdedit /set {place_new_UUID_here} device partition=D:

bcdedit /set {place_new_UUID_here} osdevice partition=D:

5. Done

Case 2: You have Dual Boot Win7 and XP/Vista and you lost the Win7 boot option at startup, but XP/Vista boots fine.

Solution:
1. Insert the Win7 Installation DVD and boot your computer with it (as if you were making an installation).
2. At the first screen , select your language etc and press enter.
3. At the second screen, click "Repair Computer" at the bottom left.
4. Wait until startup repair is finished and reboot.
5. Done. You can now boot Win7.

Case 3: You have restored booting Win7 using the Case 2 method or other way, but now you've lost XP/VISTA .

Solution: Follow Case 1 Solution.


Case 4: You want Win7/Mac Dual Boot.

Solution: Follow these instructions: OSX and Windows 7 Dual Boot