I/O devices ........................................................................................................................................................ 150
Keyboard ...................................................................................................................................... 150
Keyboard pointing stick ............................................................................................................. 151
Keyboard backlight ....................................................................................................................  151
Touchpad .....................................................................................................................................  152
Network connectivity (RJ-45 jack) ........................................................................................... 152
Network connectivity wireless (WLAN) ...................................................................................  153
WWAN ........................................................................................................................................... 153
USB ...............................................................................................................................................  154
Smart card reader ......................................................................................................................  155
Speaker, headphone - audio issues ........................................................................................  156
Thunderbolt (TB) ......................................................................................................................... 157
Storage .............................................................................................................................................................  159
Hard drive or solid-state drive not recognized ...................................................................... 159
No boot to operating system (no read-write error) .............................................................. 160
Read-write error .........................................................................................................................  161
Slow performance ...................................................................................................................... 162
Blue screen (BSOD) error ........................................................................................................... 162
Noisy hard drive .......................................................................................................................... 162
Mechanical ........................................................................................................................................................ 164
Noise (sound) ..............................................................................................................................  164
Fan runs constantly .................................................................................................................... 164
Thermal shutdown (hot) ...........................................................................................................  166
Additional information ........................................................................................................................................................  168
Acronyms .......................................................................................................................................................... 168
Blinking lights and boot error codes ............................................................................................................  169
Processor not executing code .................................................................................................. 169
BIOS recovery code unable to nd valid BIOS recovery image ............................................ 169
Memory module error ................................................................................................................ 169
Graphics Controller Error (No Controller) ................................................................................ 170
Failure System Board Error ....................................................................................................... 170
Intel Trusted Execution Technology (TXT) Error ...................................................................  170
Sure Start unable to nd valid BIOS Boot Block image ......................................................... 170
Sure Start has identied a problem (Manual Recovery Policy Set) ....................................  171
POST error messages and user actions ......................................................................................................  171
Routine maintenance for performance improvement .............................................................................. 173
Common blue screen error messages ........................................................................................................  174
Error message list ......................................................................................................................  174
Bug check symbolic names ......................................................................................................  174
Microsoft general troubleshooting of Windows bug check codes ...................................... 174
Use Windows Debugging Tool ......................................................................................................................  176
ENWW xi