Solution:

Murder.

Explanation:
1. There are signs of the struggle in the room as the clock is broken.

2. Two water glasses in the room indicate the presence of two people which also suggest that the killer is known to the victim.

3. There are a book and a pen on the bed which indicates that the dead person was reading and a suicide note was written from another pen which seems to be planted.

4. The man crutches are too far from the man.

Solution:

See the colored sticks in the picture. We have moved those sticks in the position given in the second image corresponding with the color.

Solution:

Although it looks complicated, the answer is simple. The password to his computer is JIGSAW.
1st letter of Jug = J
2nd letter of Birthdays = I
3rd letter of Fights = G
4th letter of Cars =S
2nd letter of Laptops = A
1st letter of Watch = W

Solution:

2 minutes (duration between 9:59 and 10:01)

Solution:

457730 * 4 = 1830920
(DOLLAR * 4 = QUARTER)

Solution:

A
D
C
A
B

Solution:

1 2 3 4 5 6 and 7 8 6

Since summation of numbers 1-9(1 2 3 4 5 6 7 8 9) is 45 , so its impossible to divide into two equal parts.
Since we cant flip over 6 to make it 9 but we can flip 9 to make it 6 and hence the solution

Solution:

Birbal drew another line that was larger than the pre-drawn line. Now the pre drawn line was smaller.

Solution:

The brain teaser can be solved as shown in the image below.

Solution:

The clerk said that every day the password is CHANGED. Changed is the password.

Solution:

It can be solve as shown below.