IE7 will not open and can't open options

Hello,

We upgraded to IE 8, it worked for about a week and now my internet will ot open. The window opens for a minute, pauses, with n o toolbar or address display or anything, then closes. When I try to open the internet options, it just closes. I uninstalled IE8 but cannot uninstall IE7 (as I have windows xp). I cannot get online to try anything that would require me to do so. Any help would be GREAT!!