Hello and welcome to the forums - thanks for joining!
You should be able to log on to the Market using your gmail info.
If, from your homescreen, you press "menu" and then go in to Apps/applications, ytou should get a list of all apps... scroll until you find the market and press on it. You should be able to find the option to clear cache on the market... perhaps this will help with your issue.
Hope you find this place useful!!