IE loading slow!!!!

Recently, once I open IE,it loading slow and hang about 15 to 20 second that can work fine.I try to clear the cache and temporary files but still can’t fix it.Even though I use command “sfc /scannow” to repair IE still can’t fix it.I am using IE6 with SP1 and OS is Windows XP with SP1.I would appreciate if anyone can fix this problem for me,thanks.