Macbook so slow I'm ready to commit Macbook homicide. Firefox the problem?

Question

Hello,
My Macbook has been very slow since I got it and loaded a lot of files onto it a little over 2 years ago. I compared mine to that of a fellow traveler (same model, specs, programs) and he was able to keep many programs open simultaneously and still work quickly, while I cannot run two programs at the same time.
However, now it is even slower. Some days I spend more time watching the spinning wheel than I do working. I wish I were exaggerating.
Thanks to advice on this forum, I deleted files to free 25 GB of hard disk space. I regularly repair the disk permissions. I am so frustrated with this computer that is supposed to be so user friendly and wonderful but which actually interferes with my work. I use Firefox and notice that it uses up to 50% of my CPU power. Could this be my problem?
My work requires that I keep a lot of tabs (sometimes up to 50) open in my browser. I wonder if this means the Macbook is not up to that task no matter what I do. If that's the case, would any Mac be able to handle this? I don't keep a lot of other programs open, but if I dare to use Word or Adobe Acrobat simultaneously then all the programs will stop responding. It takes 5-15 minutes for programs to even quit unless I force them to do so.
I use the latest Firefox update and Mac OSX 10.5.8
Here are my computer stats:
Model Name: MacBook
Model Identifier: MacBook2,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.16 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 1 GB
Bus Speed: 667 MHz
Boot ROM Version: MB21.00A5.B07
SMC Version (system): 1.17f0
Serial Number (system): xxxxx
Hardware UUID: 00000000-0000-1000-8000-001B631FA1B3
Sudden Motion Sensor:
State: Enabled
Thanks if anyone can shed light on my problem or help me to fix the system I currently have. I may have to purchase another computer, but I don't want to end up in the same very frustrated boat with the new one. I'm sad to say that the only time I have a bad temper is when I work on my Macbook.

Answer 1

I repair the disk every week or so lately. Just repaired it today.
You seem pretty happy with your computer overall. I definitely cannot have both Word and Firefox open without making the computer completely unusable. At some point both programs will stop responding. Even if one of them starts responding again it will only be a few keystrokes in Word or a link click in Firefox before they will both stop responding again. At that point even if I force one of the programs to quit the other one will not work well until I restart the computer.
I normally run only iCal in the background and even that I only open when I really need it. Just discovered Activity Monitor today. I have stopped running all the background programs at someone else's suggestion from several months ago.
I do think the computer is getting slower over time. I've used it as a dedicated Firefox unit for some time now but now it hangs up with even just Firefox open once I get about 10 tabs open. I am forced to restart the computer due to program hangups at least once per day. I almost never use two programs at once. I hate to have to open a PDF from the internet with Adobe Acrobat or Preview because I know I will have to restart the computer shortly. I guess I could try Safari again, but it seemed prone to crashing even with just 3-5 tabs open.
I hope the RAM will improve things enough to be workable. Otherwise it is time for a new computer and I will be sure to get the fastest one I can find rather than try to save money like I did last time.
Thanks again. Sorry I feel so bitter about this Macbook. It was fun to use for about 3 weeks and then it slowed so dramatically. But it didn't start crashing this often until maybe 6 months ago. Since then, my usage habits have gotten lighter (I was once able to use a few programs at once, if a bit slowly and with frequent brief hangups), but the computer just seems to get slower and more prone to the unending spinning ball.