Accidentally set software restriction policy that only allows powershell to be run

I was following some instructions for setting a software restriction policy, my intention was to essentially disable access to PowerShell. Unfortunately, instead of configuring the executable under "Don't run specified Windows applications" I must have added it under "Run only specified Windows applications" Now absolutely any program I try to run I get the dialog "This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator." Is there a way I can use PowerShell (since that's the only program I can run now) to remove this policy that I set?