White screen admin login

I can not login to admin.  I get a white screen and 500 error.

I ran update and got this

encoded file /usr/local/cwpsrv/htdocs/resources/admin/include/cron.php has expired

can I simply copy cron.php from my other install to fix the problem?

Tray to check button  Fast Login (no stats and checks) when you login.
tray with other firefox sometimes chrome is messing around!