The CMOS Battery is bad. The name used by Toshiba is RTC Battery. (Real Time Clock)
1) Remove ALL power. Remove the AC adapter (Charger) and Battery.
2) Follow Anti-Static Precautions.
With a laptop this means buying an ESD wrist strap, and wearing it.
Average cost is around $3 to $6. (Electro Static Discharge)
Connect it's alligator clip to a good ground source.
This is one example,http://www.radioshack.com/product/index.jsp?productId=2103245
Your body carries Static electricity. Static WILL fry out (Short Circuit), the delicate hardware components inside a computer.
Use an ESD wrist strap, and your laptop will be safe.
3) This is a pictorial guide showing, and detailing how to disassemble a Toshiba Satellite L675D Notebook PC. You'll find it also works for the Toshiba Satellite L775D Notebook PC,http://www.irisvista.com/tech/laptops/Toshiba-Satellite-L675D-L670D/dismantle-laptop-1.htm
This is Page 1. Access to Page 2 is provided at the top of the page, and bottom of the page;
Page1::Page2::Find another model (In White)
Step 17 shows you where the CMOS Battery is located. Click on the photo to enlarge. (You can click on any of the photos to enlarge)
A note on the Keyboard Cable connector on the motherboard, and removing the Keyboard;
The Keyboard Cable is an FFC.
Flat Flex Cable.
As such, it is just a flat ribbon cable with no connector, on the motherboard end of the cable,
(The Keyboard Cable is detached from the motherboard, not the Keyboard)
The connector on the motherboard is a ZIF connector.
Zero Insertion Force.
This connector is shown in Steps 9 and 10.
Click on the photo in Step 9.
Note the white rectangular 'bar'.
This part of the ZIF connector is permanently attached to the motherboard. It is stationary.
Note the two tabs pointed out by the Yellow arrows.
This part of the ZIF connector moves.
As directed by the arrows, the top part of the ZIF connector moves towards the LCD screen.
This is seen in Step 10.
The top part ONLY moves VERY LITTLE.
The ZIF connector DOES NOT come completely apart.
The top part acts like a wedge, and wedges the Flat Flex Cable in the bottom part of the ZIF connector.
DO NOT move the top part TOO FAR. As said the ZIF connector Does Not come completely apart.
If the top part is pushed too far, and the ZIF connector comes apart, it is broken.
This means Motherboard Replacement.
For additional questions please post in a Comment.