join Video Files using Command Prompt

For example if you have 3 videos in your hardrive root drive: video1.mpg, video2.mpg and video3.mpg just rename them to a, b, and c (just the letter withoug the file extension).
Example:
ren video1.mpg a
ren video2.mpg b
ren video3.mpg c
Step 2: Open Command Prompt.  Start–>Run–>type “cmd”.
Step 3: Type the location of the drive like d: or C:
Step 4: Type: Copy /b a + b + c videoname.mpg
and click enter

Step 5: Now wait till you see: 1 files copied.

And type exit and press enter. Thats it.You are done!
Note: If you want to join two files then those files must have the same extension.