[Gelöst] DualBoot Win7 + XP

Du musst die Windows 7 DVD einlegen, von DVD starten und unter Computerreparaturoptionen die Systemstartreparatur durchführen, so daß Windows 7 wieder startet, da der XP Bootmanager KEIN Windows 7 starten kann.
Sobald Windows 7 wieder sauber startet, kannst Du Dir Easybcd herunterladen und XP zum Bootmenü von Windows 7 hinzufügen.
Um solche Probleme zu umgehen, sollte man immer zuerst XP und danach Vista oder Win7 installieren.

Ab Punkt 8. wird es interessant für Dich:

Dual Boot Installation with Windows 7 and XP - Windows 7 Forums

8. Run EasyBCD.
NOTE: This is required to repair the Windows 7 boot file and add XP to the Windows Boot Manager list.

9. In EasyBCD, click on Add/Remove Entries (left side). (See screenshot below)[INDENT]
[/INDENT]10. In the bottom right section under Add and Entry, select Windows NT/2k/XP/2k3 from the Type drop down menu, and type Microsoft Windows XP (name displayed in Windows Boot Manager) for the Name. If you have selected to use a separate hard drive to install XP on than Windows 7, then select the drive letter (ex: C: ) Windows 7 is installed on from the Drive drop down menu. Click on the Add Entry button. (See screenshot above)
NOTE: You can type whatever name you would like to have displayed in the Windows Boot Manager for XP though.

11. You will now notice that this has added Microsoft Windows XP to the upper right section. Click on the Save button. (See screenshot below)[INDENT]
[/INDENT]12. In EasyBCD, click on Manage Bootloader (left side). (See screenshot below)[INDENT]
[/INDENT]13. In the upper right section under Bootloader Installer Options, select (dot) Reinstall the Vista Bootloader, then click on the Write MBR button. (See screenshot above)

14. Close EasyBCD.

15. Restart the computer to have the option to boot from XP or Windows 7. (See screenshot below)