Restoring my computer

i tryed this and it still didnt work am not sure whats wrong with my laptop because i cant restall msn messenger eitha what happened was my hotmail wasnt workin so i unstalled msn totally to restall it and now it wont let me restall it am not sure why also when i unstalled msn off my computer i got my old internet back so i tryed updating my internet to explorer 6 and it wouldnt let me update that eitha so i had to update it to firefox then i tryed to put msn on my computer with that internet browers and it didnt work maybe i have unstalled something off my computer that i shoudnt have. have you got any ideas if i could of or can u help me sort this problem out please it would be a big help if i could get msn back and explorer 6 browers back.