My computer suddenly lost all of the files that had been on my Desktop, including files inside Desktop folders. The folders themselves are still there, but they appear empty. Other files elsewhere on the drive seem to be unaffected. After restarting, Windows began showing a blue-screen error and I could no longer boot normally. A repair shop said they could not restore Windows and suggested the SSD may have been nearly full, though I'm not sure whether that explanation is technically plausible. They installed Windows on a separate new SSD, leaving the original drive available for examination. I have important illustration work and personal files from the past six years on it. A computer-forensics specialist may be able to inspect the drive, but I'd like to know whether recovery is worth pursuing and what I should avoid doing in the meantime.
2 Answers
For the future, keep at least one automated backup and preferably another copy disconnected from the computer or stored elsewhere. A mirrored drive or NAS can help with drive failure, but it is not a complete backup by itself if files are accidentally deleted or encrypted, so versioned backups are useful too.
A drive being nearly full usually does not randomly overwrite ordinary files on its own. It can cause Windows crashes, failed updates, and filesystem corruption, but the explanation from the shop is not enough to determine what happened. The blue screen might also be related to filesystem or hardware trouble, so the crash details could help, but protecting the missing files should come first.

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