Re: restore data on htc phone
You can't - this is Android, not Windows, it doesn't set restore points. (And what you did would be, in Windows, formatting the hard drive and reinstalling Windows, so you couldn't do it either.)
I'm assuming you hadn't backed the phone up (if you had you'd be doing a restore now), so about the only possibility is a deleted file recovery app. In order for that to work the phone has to be rooted (you can not - regardless of what anyone tells you - recover deleted files from the internal storage of an unrooted Android phone unless you have the hardware to access the storage chip directly, and the knowledge and experience to use it). And the apps aren't free. (I use
DiskDigger undelete (root) - easy to use and it works.)