I have purchased Keynote and Iphoto among other apps from the App store. In the past my account has worked, both at work, and on my older machine at home, a Quad Intel Mac Pro running 10.7.5. Recently I tried going to the App store to download Keynote... but could not see my past purchases. It showed that I was logged in, in the pulldown for my account there was my email... but clicking on purchases brought me to a blank screen and a link to Sign In.
Clicking the Sign In did nothing. Going to the drop down and trying to sign out did nothing.
So I says, maybe I need to trash the preferences and log in again. Google points me to the prefs, I trash em, and success, I'm no longer signed in... but the sign in links still do nothing.
Coincidentally, I can no longer open Safari. Just quits immediately or never starts. Google and Apple sites seem to say the only way to reinstall safari is with a new OS install?
I've run disk first aid, repaired permissions. There has been some slowness lately that I've had to do this (beach ball) but repairing permissions seems to fix that.