Oh and as for the button deleting. There is a famous button on the inspiron 1525 (not sure if it's on other models) called the home button. If that is accidentally pressed it boots up the system and re-partitions the hard drive and you can start up ubuntu.
There are quite a lot of people who have complained about this. I have also seen a few posts which say how to fix it but i didnt want to do it, as they said stuff like run the following code, but as im completely new to linux i didnt know where to run that code and when to do it, so i didnt do it in case your meant to type it in at a certain point.
If someone could help me with erasing the button i would be very grateful.