strange problem-need help as early as possible-OSX-BootCamp

Hai,
iam using boot camp with OSX in my MACBOOK (not the very recent macbook). Recently i got some updates from the apple, so i tried to update it. The updates stopped at 98%. Then i restarted the system.
From then, if i tried to restart MAC OS, it stops with a blank white screen forever. But bootcamp is working very fine. I can use windows. I checked the Disk utility to check the software problem, it is showing no problem with software.
I need suggestions to fix this strange problem

Thanks in advance,
Raju

Start at step 7 in this guide:

http://www.mac-forums.com/forums/os-x-operating-system/93819-basic-os-x-mac-troubleshooting.html

And let us know if that does the trick.

Some files may have gotten corrupted if you just restarted in the middle of an update.

Tried booting from step 7 of the mentioned guide.
"Package 0 didn't get an HPET" "No HPETs available"
Debugger called : <panic>

This is what appears. No active cursor to accept key commands mentioned in the guide.

Check out this article:

Resolve startup issues and perform disk maintenance with Disk Utility and fsck

If that doesn't fix it, it looks like you might have to reinstall the operating system.

i have some important data in my mac system. If i reinstall everything goes to zero. Is there any way to copy that data? and also any way to install mac OS without erasing (boot camp) windows in this situation?