I had a friend with the same problem. I told him to uninstall WAMP, delete the folder, remove the services and reboot.
* This was AFTER an extensive search on how the password/connection got borked proved to get us nowhere.
Have a cup of coffee and reinstall using the same paths as he did before - Viola - works fine now, nothing lost except maybe 10 minutes of his time.
Oh also as yfastud (and I wholeheartedly) recommend - as soon as you install WAMP, CHANGE the ROOT account password!!
Also it might be a good idea, after you got the basics of WAMP installed make a backup copy of it (like a ZIP image) in case you goof it again and you can just unzip the archive and start over. Something like a "rollback" feature