Not familiar with this problem but, if you do a clean install of any version of Windows, you are essentially wiping the computer clean and starting over. So any third party browsers (Firefox, Chrome, etc.) or any productivity apps (Microsoft Office, OpenOffice, etc.) or any other programs you have installed will be gone. Same for all of your downloads or personal documents, pictures, etc. that you have on your computer. Same for settings (favorites in Internet Explorer, personal settings in IE, other programs, or even Windows itself).
Your best bet, in my opinion: Capture the exact error message you are seeing when you try to log on and try to do some searches with the message and Windows 7. You're probably not the first to experience this. Maybe someone else found a solution or Microsoft has given some instruction on it.