hello I have XP installed computer. I am completely newbie in Unix. Despite yesterday I tried to install Free BSD 5. But I coluldn't do. So now computer is not bootable i have done wrong thing. Can you help me installing it without making Xp out of computer? please reply

You don't mention what you are getting except it won't boot. It would seem that you should be able to boot using either the XP cd or some safe mode.

As far as loading FreeBSD, here are some links with info:
FreeBSD FAQ
FreeBSD Handbook
Dual boot XP - FreeBSD
Another dual-boot using GRUB

Search both the Internet and this site for more...

I have had partitioned my disk into 3(20,15,45). First for WinXp,second for Unix and third for data. So today i reinstalled Xp without losing my data to first partition. Now I want to instsall Free BSD5. But when it comes to selecting bootmanger while installing it i don't know which option to select out of three that I can dual boot XP and UNix. Can you give me instruction that i can isntall Free BSD without losing my XP boot record and how to work with fdisk? Also before when it comes to fdisk partitioning a message says that your disks geometry is incorrect. What is disk geometry can i use G without worrying about dangerous result?
I have one disk partitioned into three and I want to install unix to second partition. Thanks in advance.