Dont know how accurate this information is Freddy but I came across this a while ago:

Laptops can be handled in the same way. If you're lucky, the CMOS battery will be under a easily accessible hatch in its own little compartment. If that's not the case, you'll need to open up the unit. First remove all the screws. You're going to need a set of very small screwdrivers. Keep an eye out for screws hidden under labels and rubber pads. Quite likely, after removing all screws, you'll need to gently pry open the laptops case.

By the way, the laptops power battery has nothing to do with the CMOS battery.

With a Toshiba you can try a loopback connected to the parallell port during the boot. This is done by connecting pins 1-5-10, 2-11, 3-17, 4-12, 6-16, 7-13, 8-14, 9-15, 18-25.


DB25
------------------------------
\ 1 2 3 4 5 7 8 ... 13 /
\ 14 15 16 17 18 .......25 /
--------------------------

With a Dallas clock, not finding a clear jumper makes things a little tricky. If the chip is labeled 'A' (DS1287A or DS12887A or DS12B887 (bq3287A)), try this: Pin 21 is a RAM Clear input. To empty the RAM, ground that.