Help with style xp please!

well i never had this problem...but i just reinstalled xp installed style xp da da da...so i apply themes etc...everytime i restart windows my windows xp go back to the windows 95 theme and dosent stick to the style xp them i add.better yet it only stays to the xp themes i put not any of the style xp themes i add.the only way it works is if i click re apply theme at start up and thats lame and slows down my xp start up any helo please!