IBM Thinkpad Laptop?

Hi I have an IBM laptop with Windows XP it has worked fine for the past couple of years. Last week I switched in on and it looks like its going to open (it goes through the windows bit) but then it says there is was a problem and it goes to IBM page. It asks how you want to open up (safe mode etc.) and no matter which one I choose it takes me back again to windows, which then take me to IBM and asks the same question. It is just continuously going round in a loop and i can get past this. Heeelp pleeeeas before I go mad! Thank you. Sue