Upgrading my computer? Any tips?

[Carlwashere]

Well I'm new to modifying my computer. This is the first computer I've opened and messed around inside of. I do a lot of research before upgrading. But I'm moving out of my comfort zone and I'm looking for tips.
Current Set-up:
Vista Home Premium 32-bit
Nvidia Geforce 9800 GT
500 watt earthwatts Antec power supply
Blackmagic intensity pro video capture card
Everything else is stock.
General Specs of my computer model

Here's what I'm planning, the memory space is pretty much maxed out for a 32-bit system, and I multi-task so much that it's usually stressed pretty well. And since it's only 32-bit, I'm going to have to upgrade to a 64-bit OS. I've never upgraded an OS before, can anyone run me through step-by-step? From what I understand, it's as easy as sticking the disc in and waiting. But that sounds too easy to change the entire operating system, at least to me.
Planned Set-up:
Windows 7 Home Premium 64-bit
more memory <--(I'm pretty sure I can pull this off easily)

and later on, I might want to change my processor to a quad-core from the dual core one I have now.
If anyone's done that before can you give me a guess on how complicated it might be?
And overall, is this a good plan?
Thanks!

[Chaavik]

I have. Quad-core CPUs are a pain to install because they have rather large cooling fans and heatsinks attached to them and are quite heavy. You have to be precise installing these types of CPUs or you can kiss the new CPU and motherboard bye-bye if it's not done properly.

I doubt 500 watts of power is enough to power a Quad-core CPU, video card, capture card (not sure what it is but I'm guessing it's related to movies or videos?), a basic DVD drive, motherboard, RAM and probably a CD/DVD burner. My partner's computer has at least 800 watts of power for what she does on her computer.

You're better off getting Windows 7 64-bit if you plan to add more RAM so the OS can use all of the available RAM efficiently. I understood there was a lot of work involved in upgrading from Vista to 7. One thing you should keep in mind.. If you want your stuff to be kept safe, BACK UP your hard drive, BACK UP your favorite files, pics, videos, mods and whatever else you can think of so you don't have to do everything all over again. Installing 7 is supposed to be easy according to one person I know, but I haven't personally upgraded yet to 7 because right now, I'm content with XP Pro for awhile until I can afford Windows 7.

Make sure you buy the right type of memory for your computer to be upgraded with.

[Carlwashere]

Hmm, If that's the case with quads I'll probably stay with my dual-core for a while.

The capture card records like all kinds of video, I'm personally using it to record old home movies and my PS3 gameplay. 

Everything is backed up now, and I've successfully installed windows 7. It's A LOT faster than Vista from what I've seen so far. Sure, it doesn't have all the programs and stuff loaded up, but from all the multi-tasking I've done so far, I'm really impressed. Right now I'm restoring all the files, I had to do a clean install of 64-bit W7.
So far, I highly recommend W7, it's making the most of my hardware, noticeably much more than vista did. I've never had XP on this set-up, so I can't offer any comparisons there. From what I read before the installation, W7 is faster than both Vista and XP.

I personally will use Crucial for memory, they've got a good reputation.

If I'd change anything of what I've done so far, it's buying the cheapest external 1TB drive. I thought I wouldn't mind the slow transfer rate. But that all changes when you're backing up a comp. It took ten hours...

Haha, if you plan on upgrading anytime soon, I can run you through the various steps I took,
Also, I suggest buying a RAID drive, 300GB doesn't move fast...