[apristel]

Well it was probably just a bad clock you installed or you didn't uninstall one before installing the next. The file i posted will usually bring things back to normal.
As far as themes, you can find them and most of the time the creator will provide installation instructions. You can do icons, sliders, taskbar icons ( the icons on top ie. signal battery, etc ).. pretty much anything you want. Don't worry about messing things up, you can always hard reset and go back to the way the phone was in the very begining. You might want to backup your contacts, for that I use PIM backup, just be sure to save the backup to the SD card. When you do a hard reset, it will wipe out everthing on the phone, but not the storage card.

Some of the ROMS have themes built-in. I highly suggest trying a MIGHTY ROM, as they seem to be the most stable. Or The Silence / Mighty ROM collaboration, that one is probably my favorite.