What virus cd should i get?

Hello,
i was doing my hotmail and my mom asked for the computer so i gave it to her. when she got do she gave it back but not untill it had shutdown from over heating. i turned it back on and loged on and did a short scane for a virus just to be safe and right before it finished it shutdown on me. it did this i dont know how many times. untill it wouldn't let me log back on. so i hard shut it down and went in throw safe mode with internet. i got to log on and did a full system scan and why it was doing that i went online and got back on my email. i checked the scan to see if it was done but it had stopped hafe way and i thought it was still scaning so i went back to what i was doing and check back i dont know how many times and it was still like that so i tryed to cansel it but it would not clouse the window so i tryed to go back to what i was doing and couldn't get to it no mater how much i tryed clicking it. so i had shut it done did the same thing 3 times in a row and each time it did the same the would not let me x out of it of let me get back to what i was doing it wouldn't even let me do the start butten so i could shut it down. so i hard shut it down and turned it back on exsept this time i didn't even try to do a full system scane i got online and finished my email and when i was done i hard shut it down and told my mom that we might have a virus that will not let us scane for it so it can be deleted from the computer she called around and was told to leave it alone and take it in so some one could fix it. but the fist thing she did in the morning was turn it on and she says she did safe mode and she says she did not tuch nuthing on the key bord but i think she did. and a blanck screen with a (-) flashing in the top left corner and i did not find out about this untill i wock up and i've tryed everything that i could think of aperently the virus turned something of that has somethig to do with the hard drive and i forget what it said it was now we are low on incum and we cant afored to fix it right now but we can get a virus dileter on a cd and i need to know if there a virus cd out there that can work with out it haveing to be on safe mode or the raguler start up screen. but if have a better solution that does not involve buying a cd or having it get fixed. if not tell it to me strait. thank you.