itunes software problems

I recently loaded itunes and quicktime onto my PC which is a 2000 pro and it worked perfectly. After I installed the same stuff onto a sony laptop that runs the same opperating system. At the end of the installing process it said to restart my computer. I hit OK but when it restarted it stalled and then frozze and ever since then it frezzes at the same spot and I cant restart my computer. Does anyone know anything about this? please help. Thank-you.