Hey this is easy to fix. This is happening because you got delete your host.MYD file, most of the time because it is an empty file.( in my computer it is always 0) to fix this open your my.ini (inside mysql installation) and find your "datadir"
In my wamp installation, it is datadir=C:/programming/wamp/bin/mysql/mysql5.1.36/data
and my standalone mysql installation it is datadir="C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.1/Data/"
Anyway m not a xampp user sorry for that. Go to that data directory and go to mysql
folder inside it. and inside that find any MYD file. We have to duplicate any MYD file. For example (db.MYD) ,, duplicate it, change its name to host.MYD. and then open newly created host.MYD and clear all the content inside it. Nw mysql should work.
HOpe this will help you.