Before reinstalling Joomla did you delete the existing joomla15
If not then delete the joomla15
folder in htdocs and try installing Joomla again this time to say xampp\htdocs\joomla
not to joomla15
then any residue from your old install that refers to joomla15
will now be invalid and you should be able to proceed.
BTW all caps in a forum is deemed to be shouting and is bad forum etiquette.25 Forum Etiquette Tips