I have one question - Are these just my problems: when opening the wp-admin at 1sthoster hosted site, very often I see just the blank sheet! What can I do with it?
They mean create a support ticket with your host so they can investigate. You can also try disabling all the plugins you've installed in WordPress as that removes a bad plugin from the list of possible issues. If it does fix the issue then enable 1 plugin at a time until it stops working again and there's your problem.
Contact your hosts support. Are you running the latest version of wordpress? If not you could try installing the latest version and maybe it will fix it. Make sure to backup your files and database first.