Macbook Pro on 10.6.8 won't boot, Help!

I have a 2007 Macbook Pro 2.4ghz Core 2 Duo with 4 gigs of Ram that was running just fine until I left for a weekend away. When I got home and tried to boot it up it gave me the "universal stop sign" circle with line thru it and wouldn't boot past that screen. I had problems with the Ram going bad before so I tried putting the stock Ram in it but nothing different happened. I tried rebooting my pram and also booting in safe mode, none of which worked. I had a disk of 10.6.3 and am able to boot from that. I went to disk utility from the DVD which when I tried to verify it it said that I had an issue that needed to be repaired. I ran the repairs and while it said it fixed them when I verify it again it still says that It needs to be repaired. So basically i've come to the conclusion that I either need to erase my harddrive and reinstall or maybe someone from this forum can help.

If I need to reinstall I guess thats what i'll have to do but my questions are as follows:

1. Since I have the DVD of 10.6.3 do I need to do a fresh reinstall of that and then do all the system updates to get me back to 10.6.8 BEFORE I do my Time Machine restore? Or can I restore from Time Machine when its still at 10.6.3?

2. If I restore from Timemachine will it also restore all my Apps? Or do I need to reinstall them from my disks and the things I purchased from the internet? (I hope not!!)

3. I noticed an option when I booted from 10.6.3 DVD that you can restore from a Time machine backup... will that fix the issues that my computer is having with trying to boot up or not? If I try this option and it doesn't work is that going to mess up my Time Machine backup or will it not effect that?

Sorry for all the questions but I hope someone can enlighten me on these issues. Thanks