Why i can't open windows 7 after installing xp on another drive?

I windows 7 on drive C, then i installed xp on drive E.

Now when booting my PC it always open on XP and not asking me which system to start

How to fix this issue? to be able to see both when boot.

Answer

Your XP install overwrote Win7's bootloader. You'll need to boot into a Win7 Recovery Console to replace it. Once that's done you should be able to configure Win7 to dual-boot to XP.

An answer to another question suggested EasyBCD -- I know nothing about the program, but it may help you out with this.

A potential 'gotcha':

• If C: and E: are on separate physical drives, your BIOS may be booting from the E: drive first, in which case your C: drive is probably fine. Try removing the E: drive and booting C: only to test. To fix, configure the BIOS or swap cables to make sure it boots to C: first.