Running really s l o o o o w ...esp. MS Office apps

Question

My machine runs pretty darn slow, esp. if I run, say, Word & Excel and Firefox, iChat and a few other small apps. I will say this, I'm running with only the 512Ram it came with and it's a 2Ghz machine. I know RAM can be a factor here. I know Office is still Rosetta, but this is painful, waaay too many spinning colored balls.
BUT...I had two crashes early on that required a complete reinstall of the OS. Each reinstall I didn't completely wipe it clean and left the previous install in (or whatever they call that...you have the old ID on the drive as "previous..." and after the reinstall a lot of settings are still there, etc.) Lastly, I have an 80G HD, with about 40 used, so it shouldn't be the drive.
Questions are:
- Should I just do a complete clean reinstall?
- Is it just a more RAM sitch?
- Should the machine go back to Apple or the Genius Bar or call AppleCare about it. This is the first time I've had AppleCare and don't feel like running to them everytime the machine sneezes.
B&W G3, 2Ghz G5, MacBook Pro, lots of boxes with wires and lights and things Mac OS X (10.4.8) used PCs plenty...but born & raised on a mac....

Answer 1

yes, ram will make a big difference, I run office 2004 on my macbook and it runs fine - with 2 gig of ram.(never get spinning beach ball)
rosetta apps, by nature, will run slower than native apps.
max out your ram, you will not regret it. 512 is just enough to run the OS.
this is the ram I bought - lifetime warranty: (read the reviews)
http://www.newegg.com/Product/Product.asp?item=N82E16820231069