Repair crashed database tables

Does anyone know how to repair crashed database tables? Our administrator login wasn’t working properly (it wouldn’t let us add new posts or update user settings). So we tried to get help from our site host Network Solutions. Please read their assessment and help me figure out how to solve this problem permanently!

“During the previous assistance, the primary cause of the site errors was crashed database tables. Repairing them through phpmyadmin should resolve them if they occur again. There is not a permanent fix as crashes are performance based. Likely the size of your database may be a contributing factor for this. It appears the database is getting rather large, The wp_options table is exceeding 300MB (and around 435,000 rows of data) due to what appears to be a order handling application is filling it up. If there is an option to remove old history through this plugin on your site, it may assist with this.”