MK300 Logitech Keyboard I do not know when CAPS are on or off. Have changed batteries there are no lights to indicate on off

The MK550 does not have a Caps Lock light on it. However, if you install the Setpoint software it will indicate on the screen when Caps lock is turned on.

My keyboard Logitech k260 Capslock Indicator not shown in my PC screen?

there should be three lights just to the upper right of the keyboard. experiment abit with your caplock key and watch the lights. Caplocks on for my particular keyboard is the center light as it seems to be on must keyboards.

For the keyboard, move the cover with a battery sign on the bottom of the keyboard to the side and you will see the battery. For the mouse, press down the rear half of the top cover of the mouse and move it backwards. The steps are on the manual about troubleshooting batteries.
http://www.logitech.com/repository/1408/pdf/24495.1.0.pdf

The Light next to the logitech logo is the "scroll lock"

Q: Changing the batteries in my MK300 How do I change the batteries in my MK300?
Wireless Desktop MK300
Model Number:
Y-R0002 (Keyboard)
M-R0006 (Mouse)
Battery Requirements:
Keyboard:

• Requires 2 AAA alkaline batteries.
• Expected battery life is up to 15 months.

Mouse:

• Requires 2 AA alkaline batteries.
• Expected battery life is up to 8 months.

Installing New Batteries
Install the batteries for your mouse and keyboard by making sure the batteries face the correct direction as shown in the image below.

Battery Replacement Tips

• For best battery performance, always use quality alkaline batteries.
• When replacing batteries, make sure the replacement batteries are new and are within the manufacturer's expiration date.
• Do not mix old and new batteries.
• Do not mix batteries of different brands.
• Do not use rechargeable batteries in this product.

underneath the mouse should be a clip/snapon port or a port shut with a screw. open it and thats where the battery goes.

You can get a new one from the nearby logitech shop or from the place where you bought it

Thanks

check this out
if u got vista, solutions seems to exist

http://www.logitech.com/index.cfm/488/558&cl=us,en

Well I guess you will know when you try typing, if there is no light indicator on the keyboard ( well there just dumb ) and you can't do anything about it.