Mac OSX Problem- HELP PLEASE!

O.K. i have a fairly complicated mac software problem. Before i go into detail, i'll tell you what i have on my computer. First, i have 2 Partitions: 1 20gb partition for windows xp, and a 140gb partition for mac OSX. I'm am running Snow Leopard.
A few days ago, i shut down my computer during the mac startup screen. Ever since then i've got this annoying progress bar that shows up every time i start up. The odd thing is, it never really finishes (it fills about 1/20th of the way before it dissappears and my computer goes to the login screen. When i log in, i am immediately plagued with problems. First, my firefox and safari say they can't "Connect to the Server" contrary to my wireless setting which insist i am connected. Second, sometimes my finder wont show up, leaving me with a blank desktop. After restarting again, i got the finder to work and quickly opened disk utility. When i tried to verify the mac partition, it told me my keys were out of order. I tried to start up from the mac Leopard install disk, but the repair disk was still greyed out.
I am considering reinstalling the mac and or making a backup and reinstalling. so now, i have a few questions:

1. My windows partition (with Bootcamp) is totally fine. I hae some Buy-to-Download programs that i can't redownload again on it. Is there any way to reinstall the mac side without reinstalling the windows side and still keep the windows partition bootable? also, will i have to reinstall boot camp?

2. Mac support and other people reccomend backing up my hard drive (with Time Machine or Manually) But if i back it up and reinstall that, wont that just reinstall the problem too?

3. One of the things that i would really like to try is to back up the whole hard drive. I have another external drive i could back up to, but if i back up the whole drive onto the portable one and erase my hard drive, How do i get the files back on my computer? and, more importantly, Will the mac and windows partitions be bootable?

Okay, i know this is a huge post
Thanks for any help in advance!

GuitarPlayer said:

2. Mac support and other people reccomend backing up my hard drive (with Time Machine or Manually) But if i back it up and reinstall that, wont that just reinstall the problem too?

Click to expand...

Why wouldn't you back it up, then reinstall from the OS disc? The backup then remains a record, and a repository of your files. Once the System is repaired, a new backup can be made.

P.S. You're in the OSX Forum. Thus, your title doesn't have to tell us you have an OSX question. And, since you're here, we can assume you're posting to get help, or advice. Please craft topic titles in the future that briefly describe the issue in your post. It's a "rule" and it's helpful.

can you boot using your install discs and then goto disk utility and repair permissions? This might fix whatever it is trying to do at the login screen... if this does not work you might have to put the verbose log in here for us to check it out. Also, do you have the latest versions of the software installed?

Also, it is not a bad idea to use Time Machine and backup regularly so that you can revert back to the previous working condition in worse case. Remember this does not work with your windows partition, but you already knew that.

Yes, you can just install OSX on the partition without messing with the windows partition in boot camp (but that should be your last resort)