Start from your startup disk. Repair disk & permissions (using Disk Utility) & things should be ok. As I said you should never be careless about deleting files. My partner deleted an entire photo shoot by accident a couple of weeks ago. I'll never let her forget it har har har lol

If worse comes to worst! If you have DiskWarrior you can (often but not always as above) fix these types of things up. Likewise with Norton Utilities (they are different.)