Sudden inability to boot up... Please help!

Question

So I've had a MacBook Pro for a little over a year now, and I have had nary a problem with it beyond simple things that could be cured with a reboot - until this morning. I shut down my computer and packed it up to bring it to work, thinking I'd get some photo organizing done in my downtime. (It was working fine this morning... I was killing some time on the web before I left for work.)
Well, when I tried to boot it up after plugging in my external HD, mouse, and the power adapter, nothing happened, save for the usual small clicking sounds of the CD/DVD drive and the standby light (holding a steady white glow). Usually, after this happens, the Apple logo would pop up, I'd hear the startup tone, etc. but absolutely nothing happened.
So I have tried the troubleshooting tips on the Apple support page, but none seemed to do anything, save for resetting the PRAM. After I reset the PRAM, I was able to hear the startup tone again (I'm thinking this may be because I use BootCamp and had it set to start up in Vista? I guess resetting this made it revert back to starting with Leopard by default? I'm not sure). I haven't changed or added any RAM (as the troubleshooting guide mentions) or downloaded any software updates for ANY of my programs lately, let alone operating system updates. However, I do believe that I am running the most recent update for Leopard.
I'm at work right now and would love to try reinstalling/repairing Leopard a try, but I can't get home to grab my discs. Does anyone have any suggestions, or maybe has had a similar problem that they were able to fix? I should note that I'm living in rural Japan at the moment and I'm at least a 3 hour bus ride from the closest city that has an Apple Store, and I'm not sure about what kinds of places are authorized repair centers in Japan, so I'd like to handle this myself if at all possible. Please help!
Two things that I should note, that may or may not have anything to do with the problems I'm having:
One, the other day, a friend gave me a CD of hers that had a photo album that she created on iPhoto on it. When I ran the CD, I noticed that the CD/DVD drive was making an irregularly high amount of noise (like it was reading the CD very intensely, scanning back and forth incessantly) and my computer became very slow at that time. I almost had to force quit iPhoto but I eventually was able to quit out and my computer returned to normal. Not sure if this has any relation whatsoever to what happened this morning, but this was the first time my Mac had acted so strangely.
Two, I noticed as I was inspecting the power adapter today that when plugged into my computer, the green LED, instead of being a super-steady light, was actually flickering ever so slightly when I looked at it really closely... is this normal? Has anyone else ever seen this kind of thing?
All your suggestions are appreciated!
P.S. If I said anything that makes me look like a complete newbie here, please disregard it... This is my first Mac after having used Windows machines for a very long time and I still don't know my way around the Mac like I do a Windows machine yet.

Answer 1

Thanks for the warm welcome Neville!
I have already tried approximately what you instructed here last night after I got home from work, and I also spoke to an Apple Japan English tech support member on the phone yesterday.
So holding the Shift key (essentially the Mac's "Safe Mode", right?) caused nothing to happen. My screen remains black for regardless of what I do and how long I do it, it seems. I also tried putting in my Leopard DVD, restarting the machine, and holding C as I boot up. This also did nothing, but I noticed that after holding C for a very long time (about 3 or 4 minutes), the standby light stopped glowing white and went dark. That was the only change I noticed. I could hear the DVD spinning and doing a lot of work, however, and also I noticed that the computer was getting warm and the fans were spinning as if it were working normally, so basically to me it seems like there's something wrong with the video. I've had video problems on other machines (albeit Windows ones) in the past that were kind of like this, and usually a swap for a new video card did the trick. I do play World of Warcraft often on my Mac and it runs at quite a high temperature, maybe there's a possibility that some part overheated?
Of course I sincerely hope that there's nothing wrong with my HD. I have a backup, but it's not extremely up-to-date as my current external HD is unusable without a reformatting for Time Machine, and I have too much data on it to just flat-out reformat. I've basically just manually backed up important files every now and again. Anything that DOESN'T involve a new hard drive would be wonderful... *sweats profusely* I'm moving back to the US in August, and you can be sure I'm going to buy myself a Time Capsule first thing.
From my description above, do you think there's any hope that the hard disk might not be the problem here?
I should also note that I also tried something that I had read in another thread here, regarding holding D on startup to run the Disk Utility, but that also seemed to do nothing.
As I said above, I talked to a representative of Apple tech support as well, and he was pretty quick to set up a service call to my place once we noted that my computer seemed to not boot from the Leopard DVD. They are scheduled to come pick up my MBP on Thursday (it's Tuesday afternoon right now in Japan)... Anyone have any other tips that I could try before then? I'd love to be able to resolve this on my own rather than having to wait a week and a half to get the thing back, perhaps stripped of my data!
This is all so frustrating considering I was using my MBP with next to ZERO problems until yesterday morning when I decided to shut it down and bring it to work... There was really no indication that anything serious was about to go wrong.
Sean