Windows 7 - i have a problem with duel boot win 7 and xp

i am using windows 7 since three months ago, however my wireless device does not support windows seven and the manufratructres don't care about upgrading it's drivers so i needed either vista or xp to run the device. i decided to duel boot win 7 with xp for i might need to sometimes use that device. i checked on the web for various methods nd i installed XP on a seperate new drive.
after the installation was complete i restarted the system and i had two option to boot with the same name. how ever i choosed frist one and xp booted.
i installed basic drivers and softwares and everything was fine and i was redy to boot to win 7
but wen in the next re start i choosed second option it says some files missing so can't boot.
then i inserted win 7 dvd and re paired it
now when i start my system i won't get any option for booting xp or win 7 but i directly boot into win 7.
Please help me how can i get that option to choose boot between xp and win 7.
thank you.

Hi vivekvr, welcome to the forums
please take a look here, I believe this has the solution

Windows 7 Startup Repair will only recover to Windows 7, then you need use EasyBCD 2.0 to add XP back to the dual boot.

EasyBCD 2.0 Beta Builds - The NeoSmart Forums

Since it's beta you have to do a quick register with Neosmart, then download, install and use Add/Remove tab to add XP. It will prompt you to add boot files, agree and Add OS, then highlight XP above and Save.