Yahoo YHT-630 System "delete multiple emails" Questions

I can't delete multiple mails in Yahoo.I mean i can't select multiple mails at a time. press and hold control on the keybourd and then the select the emails you want to delete

delete multiple checked emails. I get blank page and freeze up. Tried different browsers with yahoo. same problem only happening on my machine go to a different one it works. I did **t change anything