Keys problem ibought new laptop and now i am facing the problem of keys i mean i just understand how to use some of the keys like equal,plus,etc

You should try to explore the calculator to find its capabilities. You can also read the manual. Everything is in it.
Press the Mode button, then the down arrow key. On the second page of the mode list you find 2:Verif

An upside down image - this is caused by unintentionalpressing Ctrl-Alt plus the down arrow key. Restore by pressing Ctrl-Alt plus the up arrow key. ALSO To change the display from portrait to landscape Press Ctrl-Alt plus a left or right arrow key.

Do you need help doing your homework?

If so, here's a first attempt. It may be correct, and it may not be.
It's up to you to understand the process, and to make any needed corrections.

X minus 11 equals Y.
So, X is larger than Y.
So, 3 times X minus 33 equals 3 times Y.
Thus 3 times X equals 3 times Y plus 33.
Also, 3 times X minus 4 equals 4 times Y.

So, (3 times Y plus 33) minus 4 equals 4 times Y.

Thus 0 times Y plus 29 equals 1 times Y.

So, Y equals -27.

Hardware problem, keyboard is shorting out at different times. Keyboard needs to be replaced. Possible some water got on it or just over time keys tend to stick from dirt, dust, etc.

Easy:
1.) Turn it on ("ON" button)
2.) Hit the "STAT" button
3.) Hit the Right arrow key Twice
4.) Hit the down arrow key once or hit the "2" button
5.) Enter your Data into List one (L1) OR Right Arrow once and "ENTER" to just enter your statistics

To just Enter the Statistics:
Down Arrow once and Enter:
Hypothesis mean
Sample Mean
Standard Deviation
Number of Tests
and Either (not equal to)Ho , <Ho , or >Ho
Then either hit Calculate or Draw

If this is confusing try this website:

http://cfcc.edu/faculty/cmoore/TI83TTest.htm

The comma key on the TI 84 SE is above the 7 key, and it is just left of (, right of x squared, and below SIN. thats where the "," key is. If you're asking something else, please clearify. My understanding is that you don't know where the comma key is. 

press the plus key again, it should work. ie put a number in and press the plus key twice, it should double, and again it should double again and so on

If you are facing problem with any particular usb device then it doesn't means that the usb port of your laptop is faulty,You need to check the usb device.........or you can buy a new usb hub which is very cheap ..