It seems your laptop has been infected with the Hydracrypt ransomware. This malware changes your desktop wallpaper to a red image named
README_DECRYPT_HYDRA_ID_[8 random characters].png
and encrypts your files, adding the .hydracrypt_ID_ extension to them. The ransomware likely entered your system through malicious websites or spam emails. It’s important to address this issue promptly, as the ransom demand may increase over time. Let me know if you’d like guidance on removing it!