My phone turns on, but nothing works. The apps will not open

See if this helps: https://support.apple.com/en-us/HT201398

Hello CharlotteHoyson,

Which iPhone are you having this issue with and what iOS version are you running?

I don’t have enough information regarding the issue for me to know where to start so I’ll make some assumptions.

If you have NOT done a forced reset, you should do a “Forced Reset”. This will clear out memory and remove any old & useless data that may currently be causing strange behaviors with the phone.

I’d like to know if you had recently done a backup of your phone AND if it is a good/clean backup. Did you by chance have to do a restore of your phone, from this backup, and you’re phone is still in the “Restoring From Backup” phase and the apps are grey because they have not downloaded yet from iCloud restore, and until they are restored you will not be able to open or use them until the restore had completed.

Let me know if you need further help. Good luck.