I've dealt with error 0xc0000225 in the past, and it can be frustrating since it's often related to boot configuration issues. Since you've already tried the Startup Repair feature without success, I would recommend a few additional steps.
First, if you have a Windows installation disk or USB, boot from it again and access the command prompt through the recovery options. Once there, you could try rebuilding the Boot Configuration Data (BCD) which might help. The commands to enter are:
bootrec /scanos - This will scan for any installations that aren't listed in the boot manager.bootrec /rebuildbcd - This will attempt to rebuild the BCD store.bootrec /fixmbr and bootrec /fixboot - These commands can help repair the master boot record and the boot sector.
Make sure to back up any essential data if possible before making major changes, as there's always a risk of data loss. The BCD repair often resolves these issues, but if it doesn't, there may be a more in-depth file integrity issue.
As a quick tip, some users have found success by physically checking their hardware connections, such as reseating SATA cables on the hard drive, which can sometimes contribute to error 0xc0000225 due to loose or faulty connections.
If these steps don't work, you might need to consider using system restore points, assuming they're available, to return to a prior stable state.
For in-depth information, Microsoft has useful support documents, and communities like Super User and Microsoft Answers often provide step-by-step troubleshooting guides tailored to specific issues like this.
Let us know how it goes or if you need more detailed instructions on any of these steps!
