yea, you definitely need a hard reset. i recommend 1 of 2 options. if you dont have much free time and dont care to learn about your phone, just flash to the newest sprint rom, there is one with GPS enabled somewhere out there, dont know if it's officially gone on htc's website or not.
the better option (and much more time consuming) would be to upgrade to one of the custom roms. it will teach a bit about your device, and you will feel much more confident in what you do with it later on. i believe the most popular roms these days are dcd's rom and nuerom. personally i use neurom (if you like it, no2chem is accepting donations, he is just a student, he could use them), it is very minimalistic and runs quite nicely. yes, i do believe it is possible to brick (make it unusable) your phone if you mess up, but i've never had this problem and if you have the insurance, which i recommend, you can just get it replaced. here is the link to that rom:
http://forum.ppcgeeks.com/showthread.php?t=17219
and yes, with either option, and with just getting your phone replaced, definitely back up your data, especially your contacts. you should be doing that anyways, many of people have lost their contacts from one glitch or another, activesync is buggy. i would recommend creating backups outside of outlook as well as i've heard of people having their outlook contacts deleted.
hope that helps,
Ryan