Can't boot windows xp directly , boot.ini have error ?

What exactly is error and when do you get it?

Do you get into windows at all?

Have you tried anything so far, if so what have you tried?

Any changes that either happened or that you perhaps made to your computer around the time that the problem started; particularly any Software or Hardware that you installed or setup.

Put the Original Operating System Disk in the drive and reboot the computer, select the boot option to boot from disk and during the XP setup, selection, select option 2, Repair using the recovery console. At the DOS prompt, select the particular installation (usually #1) and supply the administrator's password (note, this is the actual account named Administrator, not any other user who was created and given Administrator status).

At the C:\Windows prompt, type CHKDSK /r and let the recovery console run, depending on how severe the issue is, it could take up to an hour to finish.

Check out the following for information:

Advanced troubleshooting for general startup problems in Windows XP

10 things you can do when Windows XP won't boot