If you choose, the best way to solve the issue is to do-away the Windows managed dual boot and use the BIOS to choose which OS you want to boot when the PC is first started.
It's fairly simple process, first, disconnect the Hard Disk Drive (HDD) that has Windows XP installed to it and leave only the Windows 7 HDD connected, then you mark the Windows 7 partition as "Active" then do 3 separate
startup repairs with a system restart between each repair
to create a set of boot files just for Windows 7 so that it will be able to boot independently of XP.
When finished and Windows 7 is booting on its own then reconnect the XP HDD and that's it, they will now boot independently of each other using the BIOS boot menu.
It's not as big a deal as it sounds, have a look at the tutorial at the link below for all the details. Startup Repair - Run 3 Separate Times