Nice files, but if you want a better defrag job (ONLY for Windows XP), also include 'defrag c: -b'
The -b option is not listed under the help of 'defrag' but it is there. It will defragment the prefetch files of the disk drive it's defragmenting, which will significantly increase boot up speeds. The other changes I made put 'defrag' into verbose mode to spit out more information, and I also made it output it to the same 'disklog.txt' file, instead of just to the screen.

In my opinion, an improved version of the batch file.
chkdsk > disklog.txt
defrag c: -v > disklog.txt
defrag c: -b -v > disklog.txt
disklog.txt