Follow these steps:
• Insert the SQL Server Installation disc into the server computer's disc drive. Access the drive from your computer by clicking "My Computer" from the desktop and double-clicking the disc drive icon.
• Run setup.exe from the SQL server installation disc. The setup command should be located in the disc's root directory. Run the setup program by double-clicking "setup.exe." This will bring up the SQL server installation center page.
• Click the "Maintenance" button located on the lefthand side of the navigation window. Select "Repair" and then choose the language you wish the program to be presented in after installation. Click "Next" to continue. This will run setup routines, making sure your computer has all the prerequisites installed to correctly run SQL server 2008. Click "OK" or "Install" to continue. This will bring you to the Select Instance page.
• Select the instance you want to repair. This will reconfigure your server using automatic backups to a time the server was working correctly and reinstall any corrupted information. Click "Next." The repair rules will automatically verify the operation. Click "Next" to continue. This will take you to the Ready to Repair page.
• Click "Repair" and SQL server disc will run its repair function. The repair progress bar will show the completion level of the repair. Once the repair function is complete, click "Finish" to exit the repair program. Reboot the server machine to complete the repair.
Also see info on this Microsoft site: https://social.technet.microsoft.com/Forums/itmanagement/en-US/373cf033-d3f1-4f71-af02-a8a6b8d05828/sql-database-is-corrupted-plz-help?forum=sqltools