I had the endpoints on snap on and I tried to snap a line at top left corner but the cursor was jumping around,does anyone know how to fix this?

Hit F9 to turn off your SNAP, or you can click on the icon second from the left end of your status bar.You can cycle it on and off with F9.The system variable name for it is SNAPMODE, but easier to click on it or use F9.

your cursor was jumping around due to your snap mode is on F9 is function key Toggle snap mode ON/OFF

or your can use Snap commend and off snap mode.

make "snap off " (f9)  and try 

I leave the answer specialists experts in the field .

i am totally agreed with the answers of above professionals. u just have to put off the snap mode through F9.

Should Press F8 to OFF Snap

Hit F3 TO OFF Osnap, THEN TYPE YOUR COMMAND AND HIT ENTER CLICK RIGHT TO YOUR MOUTH THEN SELECT YOUR POINT

we have to press F8