My pc doesnt boot up

Hi all,

Iwill really appreciate if some one can walk me trough with my pc.It doesnt boot all. Every time , I put the power , I can see the cursur at the top on the left and doesnt do anything.Actually , its a built pc with XP PRO. i had problem with “NTLDR MISSING” before then wanted to reinstall os xp again to get it fix. Now ntldr is gone but it doesn’t boot at all. Thanx for your help