i lost BIOS Password

You must place a call to Dell support.  Be prepared with verification of ownership of the system, and if the system is out of warranty, with a credit card to pay for the call.

I can not call to Dell support because it is very expensive I am in Egypt

you should be prepared to disconnect your CMOS battery and that should resolve your problem.

The password is stored in nonvolatile EEPROM - removing the battery will do nothing.

The only other legitimate alternative to calling Dell support is to replace the mainboard, which will likely be several times more expensive than calling.

i try remove battery but password not change.