Computer won't run anything: my computer was being a little slow yesterday and today while working i received a hard disk error message. I started to defrag the disks in case that'd help but had to be somewhere and couldn't complete the process, and admittedly wasn't as concerned as i should have been. I started it up just now and it won't run anything-when running Windows it just halts on the logo, when running startup repair all i got was a black screen and white arrow, nothing more, same result it seems with trying to reinstall. No problems with my computer formerly.