Does it do nothing at all when you turn it back on? If it lights up, press the Function 8 key and see if you're offered the Advanced Boot menu starting with Safe Mode.
If you see that menu, select "Disable automatic restart on system failure" then you should see a blue screen with a Stop Error message. Note the numeric code 0x0000?? and ANY_WORDS_JOINED_UP by underscores and post it all back here.