Here's a trick to really get the defrag right, if you have the disk setup to do it.
It requires a second partition with enough space to hold the full AH directory.
Copy your AH folder to a temporary directory on a different partition. Once the copy is done and successful, delete the original AH folder.
Now defrag the drive AH was on. Once the defrag is complete, then copy your AH install back to the original, freshly defragmented drive.
This works MUCH better than just a defrag, as the windows defragger isn't really very smart. This method not only makes sure that files aren't fragmented, but that all the AH stuff is more or less on contiguous disk area, instead of all over the drive.
One more thing: If you don't have the spare drive, you can just copy all your configs to safety, and delete your AH directory, then re-install after the defrag.