I bought a PA-13 to use with my Latitude D800, and I have used an HP and Targus I own as well, however is this harmful???

try to adjust the backlight of the LCD by pressing and holding the FN key and press the up arrow key. also try to update the video/graphics driver of your Dell Latitude D800 . you can download it here: http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=19&l=en&s=dhs&ServiceTag=&SystemID=LAT_PNT_PNT_D800&os=WW1&osl=en&catid=&impid=

You can reset the windows password by using 3rd party tool.

you can visit this site (there are options for the tools and intructions how to do it)

http://pcsupport.about.com/od/toolsofthetrade/tp/passrecovery.htm

replace either your cold cathode screen lamp or, your inverter board in your display

Select your model on website below to download drivers:


Dell Drivers and Downloads

what do the Lock Lights indicate (Flashing , ON, ON perchance) it appears that the CPU is either not compatible or bad. Have you tried the original porcessor?

Try purchasing an original adapter. I've had several machine of different make through my shop that the Targus adapter just simply won't run. For example, a Dell Inspiron 1100 and HP dv4000 won't run at all, and a Dell Latitude 1501 and Gateway crv503 will run but won't charge the battery. Targus adapters are junk, if you can, get your money back.

This is the SpeedStep technology feature of your processor. It will speed back up to 1.7 GHz when it is needed. Slowing down the processor saves battery life.

This may be SpeedStep slowing the processor to save battery life. It speeds up when it is needed.

Try re-installing windows.