@mtpeke, Hey, I love reading your posts because they remind me of the innocent android user I use to be. OK, let me try to get you straight, the best I can.
1. You are rooted because you can use wireless tether. You would not be able to use wireless tether if you were not rooted.
2. You can tell us what your version of Recovery is by doing the following:
- Shutdown your device (not reboot)
- turn on your Droid, holding the X key at the same time on the keyboard. Don't let go until you see the Recovery screen.
- Look for the version of Recovery or any clues we can use (like do you see the Android Logo, do you see green text, what the text says, etc.)
3. You should download MyBackup Pro or Titanium (the paid edition) and backup your applications and data. Also backup your system data (that has email info, contacts, etc.) btw, you don't need to backup your contacts because they are already backed up using Google automatically, but you can if you want.
4. download a new rom (maybe Gingerbread 2.3 based) by looking through the forum, here. Click on forum, and go to custom roms.
Custom Roms
5. put the Rom in the root of your sdcard. Rename it update.zip (the update.zip name depends on the Recovery version, as this should be compatible with old and new versions of Recovery software).
6. Wipe your phone using the option in Recovery 3 times. You would wipe both data and system. Make sure you are not in any options to wipe or format your sdcard. These are two different options!!!!
7. select the option to install the update.zip Rom.
8. Reboot the phone, using the option in Recovery.
9. Configure your phone for first time setup.
10. Go to android Market, and install My Backup Pro again (or whatever you used to backup your stuff)
11. Restore your stuff
12. Now your phone is updated with a new Gingerbread ROM
Disclaimer: if you end up bricking your phone, it's not my fault.