HELP! Database problem

[Lorraine-H]

3.8 Forum been working fine up until now.

Now main forum page loads fine but clicking on any thread, New posts, etc and I get:

Database error in vBulletin 3.8.4:

Invalid SQL:

SELECT post.pagetext AS preview,
thread.threadid, thread.title AS threadtitle, thread.forumid, pollid, open, postusername, postuserid, thread.iconid AS threadiconid,
thread.dateline, notes, thread.visible, sticky, votetotal, thread.attach, thread.lastpost, thread.lastposter, thread.lastpostid, thread.replycount, IF(thread.views<=thread.replycount, thread.replycount+1, thread.views) AS views,
thread.prefixid, thread.taglist, hiddencount, deletedcount
, NOT ISNULL(subscribethread.subscribethreadid) AS issubscribed
, deletionlog.userid AS del_userid, deletionlog.username AS del_username, deletionlog.reason AS del_reason
, threadread.readtime AS threadread
, threadredirect.expires

FROM thread AS thread
LEFT JOIN deletionlog AS deletionlog ON(thread.threadid = deletionlog.primaryid AND deletionlog.type = 'thread')
LEFT JOIN subscribethread AS subscribethread ON(subscribethread.threadid = thread.threadid AND subscribethread.userid = 1 AND canview = 1)
LEFT JOIN threadread AS threadread ON (threadread.threadid = thread.threadid AND threadread.userid = 1)
LEFT JOIN post AS post ON(post.postid = thread.firstpostid)

LEFT JOIN threadredirect AS threadredirect ON(thread.open = 10 AND thread.threadid = threadredirect.threadid)

WHERE thread.threadid IN (0,10144,10171,10114,10037,9999,9965,9615,9659,866 2,8867,8651,3954,8611,8932,8342,9109,9118,8927,872 2,7786,4)
ORDER BY sticky DESC, lastpost DESC;

MySQL Error : Table '.\forum\post' is marked as crashed and should be repaired
Error Number : 145
Request Date : Sunday, April 4th 2010 @ 07:36:40 PM
Error Date : Sunday, April 4th 2010 @ 07:36:41 PM
Script : http://www.equine-world.co.uk/horse-...isplay.php?f=5
Referrer : http://www.equine-world.co.uk/horse-forums/index.php
IP Address : 86.26.27.163
Username : Lorraine
Classname : vB_Database

Tried to login to admin - can login ok but the admin page then displays:

Database error in vBulletin 3.8.4:

Invalid SQL:

SELECT COUNT(*) AS count
FROM attachment AS attachment
INNER JOIN post AS post USING (postid)
WHERE attachment.visible = 0;

MySQL Error : Table '.\forum\post' is marked as crashed and should be repaired
Error Number : 145
Request Date : Sunday, April 4th 2010 @ 07:39:38 PM
Error Date : Sunday, April 4th 2010 @ 07:39:38 PM
Script : http://www.equine-world.co.uk/horse-...ex.php?do=home
Referrer : http://www.equine-world.co.uk/horse-...incp/index.php
IP Address : 86.26.27.163
Username : Lorraine
Classname : vB_Database
MySQL Version : 5.1.37-community

How do I fix this?

[Zachery]

The post table is marked as crashed and should be repaired