[BellaBella]

Whenever I try to restart my computer it lags for a long time (after the desktop becomes blue, it just sticks there). Then when restart by holding down the power button, the computer doesn't boot up (stays on the grey apple screen) and the only way I can get it to restart properly again is by running DiskWarrior from the disc. This happens almost everytime I try to restart. I don't know what to do

[bowwowman]

FYI, posting your machine model & specs & OS version might help with troubleshooting.....just a note for future reference

The next time you have the machine running, open system preferences, open the Start-up disk control panel, and select (highlight) the drive you want to boot from, then clik on the padlock at the lower left corner to lock it, and restart.......see what happens

if this doesn't help, you may have to trash the sud preference file, empty the trash, restart again, and redo the above step, and restart once more to verify....

if neither of the above works, then your HD may be almost full, or in the early stages of failure.

[jmiddel]

Sounds like a hardware failure. This hapened on mine and my wife's computers, in her cas the HD was failing, in my case the video card was going bad.