Your external USB 3 HDD may work on your old laptop which only has USB 2. Most of the USB 3 will work on a USB 2 if you have the proper speed cable. It will only operate at the 2.0 speed, however.
I dont know how to do it. Is there anyone who can answer this question....
A laptop runs on DC. Either from the battery, or the external power supply, which converts AC power to DC.
If you've got a "good" enough laptop, absolutely! You'd probably want to attach an external mouse with a scroll wheel.
A battery on a laptop serves its purpose of allowing you to take your laptop with you away from external power sources (ex. ac outlet). They can also work like uninterruptable power supplies as if you have the laptop hooked up to an outlet yet the power goes out for a minute, your work is safe as the power will not shut off.
Check your settings.
There is only one way to fix a laptop that has a shift button that does not work. You will have to take it to a computer shop and have it looked at.
Only will work if it is on sleep, not off or hibernate.
Laptop cooling trays only work for very hot computers. If you have a gaming laptop, consider getting one.
If you want ONLY the usb one to work, you could disable or uninstall the driver for the one on the laptop. press the windows key, type device for device mngr, find your keyboard, and you are there.
No. As you said, they are both outputs. Both are designed to send their signals to an external display. The only current HDMI- compatible connector on a computer that can be reconfigured as an input is the DisplayPort connector on the 27" iMac.
So that you can take your laptop home and work on the same work that you did at work,
A MacBook is considered a laptop. If your asking if a Windows machine is better then a Mac machine then only you can answer that. Do your home work and look at both.