'why the ligth for the uppercase letter function flashing for 9 times and the dell d600 don t start

This indicates when the uppercase letter function is enabled.

See the manual here http://downloads.dell.com/Manuals/all-products/esuprt_laptop/esuprt_latitude_laptop/latitude-d630_User%27s%20Guide2_en-us.pdf

Page 99 says the three LED indicators for Num Lock, Caps Lock, and Scroll give the POST error status, and the reason for not starting up. Then contact DELL customer service for assistance.
Check these and then contact

Turns on when the numeric keypad is enabled.
Turns on when the uppercase letter function is enabled.
Turns on when the scroll lock function is enabled.

Those are Diagnostic indicators that point you to the possible cause. The padlocks will have a number ( Turns on when the numeric keypad is enabled.) or capital letter(Turns on when the uppercase letter function is enabled.) or arrow key(Turns on when the scroll lock function is enabled.).
According to those indicators you either have a bad memory module or your CPU (processor) is bad.

Turns on when the numeric keypad is enabled.

Turns on when wireless devices are enabled.

Turns on when the uppercase letter function is enabled.

Turns on when Mini PCI functionality and Bluetooth® wireless technology are enabled. To enable or disable Mini PCI functionality and Bluetooth wireless technology, press <Fn><F2>.
NOTE: Bluetooth wireless technology is an optional feature on your computer, so the icon turns on only if you ordered Bluetooth wireless technology with your computer.
For more information, see the documentation that came with your Bluetooth wireless technology.

Turns on when the scroll lock function is enabled.

Here is the answer! memory problem! go to this site. http://www.laptop-junction.com/toast/content/dell-caps-lock-light-flashing-blinking

To the right of the power button and below the Dell AccessDirect button are three lights. These have a lock synbol below them. The first one from left to right is signified by a number 9, this light is turned on when the numberical keypad is enables. The center light is signified by a letter A, it is on when the uppercase letter function (Caps Lock) is enabled. the third one, far right, signified by a down arrow, is on when the scroll lock function is enabled.

The device status lights on the far right side near the front of the laptop case. The top light is the power status light, the middle light is the Hard drive activity light, the bottom light is the status light for power management, battery, AC etc.

I did not understand the problem but If I understand mouse ligth comes on but laptop is not function? If this is the issues. There is a button works for lock the keyboard and mouse which is causes the laptop mouse ligths comes on everytime. You need to located and press this. Mostly on front panel where is under the LCD. close to power button or Audio buttons. Try this if this is the issue.
JMC

The Caps Lock Flashing then going off is a power on self-test code. Here is the Dell troubleshooting guide to the issue.

http://support.dell.com/support/topics/global.aspx/support/dsn/en/tree?c=us&l=en&s=gen&journalid=&treeid=084A4C3E0A9C9EEEE0401E0A55172321&Query=&SystemID=&ServiceTag=&contenttype=&os=&component=&lang=&doclang=&toggle=&dl=

From my experience, if removing al customer removable devices failes to make the system post properly, the motherboard will need to be replaced

The flashing battery light is an indication that the system is attempting to charge the battery. The orange light indicates a problem charging one of the battery cells. This usually means that the battery either needs to be recalibrated or replaced. To recalibrate the battery just use the system until the battery is dead, then recharge and repeat the process twice, after which time the battery should be recalibrated. If this doesn’t fix the flashing orange light then the battery may need to be replaced.

hope this helps

the charger in the laptop is not functioning. pc will need repaired

Try pressing firmly on the keyboard around the 6 and 7 keys and pressing the power button at the same time. Works with my D600 which has the same problem. Apparently it is a common problem with something looses or not soldered properly under there. Will eventually get around to pulling mine it apart to see if I can fix the problem permanently but this "fix" has been working for quite while now.