Lenovo ThinkPad W700ds - Manual (Page 26)

If one of the following error code messages is displayed on the screen, have the
computer serviced:
02F4: EISA CMOS not writable
02F5: DMA test failed
02F6: Software NMI failed
02F7: Fail-safe timer NMI failed
Fan error
Thermal sensing error
Errors without messages
Problem:
When I turn on the machine, nothing appears on the screen and the machine
does not beep while starting up.
Note: If you are not sure whether you heard any beeps:
1. Turn off the computer by pressing and holding the power switch for 4
seconds or more.
2. Turn it on and listen again.
Solution:
1. Make sure that:
v The battery is installed correctly.
v The AC adapter is connected to the computer and the power cord is
plugged into a working electrical outlet.
v The computer is turned on. (Turn the power switch on again for
confirmation.)
2. If a power-on password is set:
a. Press any key to display the prompt for the power-on password. If
the brightness level of the screen is low, increase it by pressing the
Fn+Home.
b. Type the correct password and press Enter.
3. If these items are set properly, and the screen remains blank, have the
computer serviced.
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ThinkPad ® W700 and W700ds Service and Troubleshooting Guide