What does it mean when my laptop has a white screen?

Today when i started my laptop up a blue screen came on saying Umountable Boot Volume. What does that mean and can it be fixed

• My laptop is a Windows Vista and there is no installation disc there wasnt one when i bought the computer

• Answer:

  The master boot record has become corrupted, so when you boot the computer cannot find the necessary instructions to mount the hard drive. You may need to have a Vista system disk to repair it. Here are some instructions I lifted from the web which explains what needs to be done in that situation. http://answers.yahoo.com/question/index?qid=20100826110232AAwCffg I have repaired several machines running XP, but there you go into recovery console via the cd, which Vista does not have - but this person (Answer 4) describes a very similar process specific to Vista. If you did not have a systems disk when you bought the machine, it is likely that all the files are present on the hard drive in a hidden partition, and if so, when you press a certain key, probably F12, on the keyboard, you should see other options besides the repair described in the Yahoo answer, one of which will be a restore to original settings.There might be other restore options offered that will do a copy over of system files and not remove anything - it should be clear what each option offers. If you have to go for the original state option, to avoid losing all your personal stuff ( but you will lose applications), you could take your hard drive out and connect it via usb with an external cable set ( Amazon sell them) to another computer to get all your stuff off, save it to an external drive, and then connect the external drive to your own computer when the hard drive was back in and the system restored and put them all back on again ( sounds harder than it is). You have to be sure and buy the set that has the same fitting as your hard drive ( SATA or IDE) of course, and has a connector for laptop hdd's. Otherwise, take it to a friendly geek to do the necessary.