PLEASEEEEEEEEEE!

i have a dell laptop and for the past few weeks it has refused to start up and comes up with the message "delayed write failed". another message said to uninstall anything that had been recently installed but when i go to unstall a programme in safe mode it won't let me.

my flatmate tried a disk clean-up. nothing.
theo? suggested i change the disk caching. nothing.

help, please. anyone?