I have attached a file called mysql.txt. You need to change the file extension to .reg and then double-click it to make the reg entry.
I suggest you take a backup of your registry first - just in case.
Then go to "Start -> Control Panel -> Administrative Tools -> Services" and make sure that there is a mysql entry in the list of services. You might need to right click on the entry and set "Startup type:" to "automatic".
Let me know how you get on.