@Tushar Debnath, Thanks for posting in Q&A.
To use Proactive Remediations to delete a registry key, here is a link with an example for your reference:
https://andrewstaylor.com/2022/04/12/proactive-remediations-101-intunes-hidden-secret/
Note: Non-Microsoft link, just for the reference.
I notice you want to delete a registry key. You can change the "new-item" command to "Remove-ItemProperty" to meet your requirement.
Here is a remediation script example for your reference:
Start-Transcript -Path $env:TEMP\DisableFastBoot.txt if(Get-ItemProperty -LiteralPath "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Power" -Name "test") {Remove-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Power' -Name 'test'; write-host "Value delete"}; Stop-Transcript
Note: You can change it according to your requirement.
Hope it can help.
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