I need some help guys

I have a computer and had windows 7 on it..I ran into problems and I decided to switch to ubuntu 12.10

So after a I installed ubuntu (live USB not wubi) I rebooted and when I did I boot from the HDD but all it did was take my to a blank purple screen.. A few minutes later ubuntu came up on the same purple screen and it started to load but then the purple screen disappeared and all this text came up that continuously kept changing (I'm new so sorry if I phrased that wrong)

It said something like buffer I/O error on device sda logical block and them a load of numbers

My HDD was absolutely fine up until this point..so ubuntu is on my computer but I can't access it on my HD only through the live USB

Please help!