Boot from winxp cd & go to Recovery Console :
When you boot to the recovery console the default prompt wud be C:\Windows
Type cd.. (including the 2 dots) & it will take u to the C:/ prompt & then type in the following commands
1. Attrib –H –R –S Boot.ini
2. Del Boot.ini
3. Bootcfg /Rebuild
After each & every command u have to press enter. After doing Fixboot take winxp cd & restart the system.