dead end error message – pulls up after loggin in – can't access website

our wp website is really screwed up.

for some reason the domain pulls up but it even shows error messages on the domain and does not show the content pics etc.

when logging in through WP this is what comes up (after typing in log in information)

Warning: Missing argument 2 for wpdb::prepare(), called in /home/content/24/9544924/html/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 176 and defined in /home/content/24/9544924/html/wp-includes/wp-db.php on line 990

Warning: Missing argument 2 for wpdb::prepare(), called in /home/content/24/9544924/html/wp-content/plugins/buddypress/bp-core/bp-core-options.php on line 293 and defined in /home/content/24/9544924/html/wp-includes/wp-db.php on line 990

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-login.php on line 368

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-login.php on line 380

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-includes/pluggable.php on line 680

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-includes/pluggable.php on line 681

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-includes/pluggable.php on line 682

Warning: Cannot modify header information – headers already sent by (output started at /home/content/24/9544924/html/wp-includes/wp-db.php:990) in /home/content/24/9544924/html/wp-includes/pluggable.php on line 876

this message shows up and nothing else comes up – no dashboard or any other options –

any ideas?

thanks much!

regards