Can't boot in Mac OS (Always Windows)

[Siro]

Hi.

I have Leopard and Win XP (partition created by bootcamp). I was using Mac OS, and Windows was used only in emergency situations. Everything was all right, until I had to use Windows again. I started it by "Startup Disk" in Leo, did what I supposed to, and selected "Reboot in Mac OS X". Then, my Macbook restarted and booted in Win again... I rebooted again holding "Option" and selected Macintosh HD. System which started was Windows again. I tried to reset NVRAM, it went OK, but again system which is booting by default, or from Startup Manager is still M$ Windows. Safe Mode or Single User Mode won't start. I don't have my Leo DVD because I'm not at my place (so i can't run disk permission or smth), and I need to run Mac OS.

Is it possible to somehow force this Macbook to run Mac OS X without reinstalling or even using install DVD? If not, what should I do after aquireing this DVD?

Thank you in advance for any advices.

[Giaguara]

Alt (option) should give you all the bootable options. If it still seems to get to windows, select restart from your Windows menus, and keep alt again until you get to Mac OS X. Sooner or later you should hold the key at correct time (just after POST).

[Siro]

But the problem is, that I am pressing it at the correct time, and I can choose between Macintosh HD and Windows disks. I'm selecting Macintosh HD, and it's still starting in Windows.

[Siro]

Problem solved after inserting install DVD, and selecting Mac OS as a startup system from there.