I want to restore my old OS (xp).

Hello,

I have a very loving old Laptop Compaq 2210b. It came with Windows Vista installed and I didnt like Vista a lot so I got my dealer change the OS to XP. I was happy with the laptop and XP when suddenly I saw that I cannot go into safemode to run a virus check which I usually do. after listening to a concerned friend who sugested that i change the boot oftion to safemode, I did something i dont remember(something related to the Boot.ini file i think) which kind of finished the whole issue. My PC wont go into safemode and I had changed the boot option to safemode.
Now another friend has re-installed XP on another drive on my PC. The result is now i can start my PC. Can somebody suggest a way to fix the previous problem from the new OS installed.

HELP!

Thanking in advance