Misc Windows SBS 2003 issues in event log

We have an old Windows SBS 2003 Server that recently had some corruption of it's SAM database. We repaired the corruption and replaced it's hard drive as well, but the server has since been still randomly rebooting and we've been losing connectivity to network shares Some of the errors in the event log include: - Error initializing session for virtual machine XXSERVER. The error number is 0x8004011d. Make sure Microsoft Exchange Store is running. It is running. - The SAM database was unable to lockout the account of Administrator due to a resource error, such as a hard disk write failure (the specific error code is in the error data) . Accounts are locked after a certain number of bad passwords are provided so please consider resetting the password of the account mentioned above. - The reason supplied by user XXXX\Administrator for the last unexpected shutdown of this computer is: Other (Unplanned) Reason Code: 0xa000000 Bug ID: ok Bugcheck String: Comment: ok - The Routing and Remote Access service terminated with service-specific error 1168 (0x490). - The DHCP service has detected that it is running on a DC and has no credentials configured for use with Dynamic DNS registrations initiated by the DHCP service. This is not a recommended security configuration. Credentials for Dynamic DNS registrations may be configured using the command line "netsh dhcp server set dnscredentials" or via the DHCP Administrative tool. We need to tidy this up and make the server stable as soon as possible.