Can some of u help ???

You will have to boot on your linux using some kind of rescue linux or live cd (the last is better I think), and run Lilo or Grub install again. Then you will be able to boot your system to linux again.

If you partitioned your hard drive then the PC should be seeing those partitions as different drive letters. You might be able to get your PC to boot the Linux operating system by changing the boot drive in the bios. Most PCs you just hit delete during the boot to get into that and see if you can find where to change the boot drive.

The problem is that Linux installed either GRUB or LILO into the MBR on the Windows partition. These are boot managers that produce the interface at boot which allows you to select the operating system. After reinstalling Windows the boot manager no longer exists, so the computer automatically boots into Windows by default. You can start the computer by using a Live CD containing Linux, which you can download quite freely from the internet. You then should be able to reinstall the boot loader (either GRUB or LILO) and regain access to your Linux system.

Did you parition your hard drive and install windows on one partition and linux on the other, if you didn't windows might have overridden the boot setting on you computer or even worse perhaps it formatted your hard drive causing you to loose all your original files (check to see if you can see them from windows). Last time i tried doign this i used Partition magic

Windows prefers not to see Linux partitions so if you go into my computer you probably will not see your Linux partition. What distro are you using and what boot loader are you using. I suggest Ubuntu for newbies and the grub boot loader.