Well, Fear, I'll give some info and leads on how to proceed when you do get down to the nitty gritty.
Turning on the computer without a power button is actually a simple task. It involves finding the pwr_btn or similarly named pin and the ground pin horizontally next to it. Then, you short circuit the pins by touching them briefly with a screwdriver. If the computer struggles to turn on using this method, then the likely culprit is the power supply.
Here is a vid (and there are others):
[media]http://www.youtube.com/watch?v=G4FOBL1c3pA[/media]
You first want to identify the wires that connect the power button of your computer case to the pins on the motherboard. You have to pull out the header to get to the bare pins. The header is just the rubber end with a couple holes you push into the pins.
---------------------------------------------------------------------------------------------
2) PC times out a lot. The processing freezes up. During these episodes, I can move the mouse/cursor around, but can't get it to respond to any clicks, or even move from one browser to another. Goes into "Not responding" mode. Not sure what else to call it. But it lasts a minute or 2, until it finally "finally comes back into consciousness". It is more likely to happen if I have multiple browsers open, but has even been known to happen with just one browser in use. I have done a complete clean-up on my PC, to check for virus, spyware, malware, etc. Besides that, I've cleaned it up using some of the programs suggested in other threads, such as CC Cleaner, Disk Redactor, Windows Washer, and Disc Defragmentor. So, as far as I know, my PC is clean. But still has the problem. Could it be I just need to upgrade the memory ?
Here are the specs :
OS - Windows XP 2002, Service Pack 3
Processor - Intel Celeron CPU 2.80 GHZ
496 MB RAM
The constant freezing and nonresponsiveness is partly due to the processor being slow as a sloth and partly due to having not enough RAM.
What happens when you don't have enough RAM is that the hard drive's paging file(Windows) or swap partition is used as "extra" RAM. But data and processing instructions travels much more slowly than between the hard drive and CPU than it does between the RAM and CPU. The result is a lot of "noise" from inside the case due to the hard drive seeks that result from using the pagefile as RAM.
You definitely have insufficient RAM for modern day programs. Firefox and Chrome are memory guzzlers and can gobble up 1GB of RAM easy these days. Open up Task Manager while your loading your computer with typical programs you use. The RAM usage it shows will likely be greater 496 MBs of RAM if you load up a couple brows with a bunch of tabs. If you were to upgrade anything, upgrade the ram first.
From the specs you listed, I suspect you have a Celeron processor from the Pentium 4 era. Don't be fooled by the GHzs, those processors are slow, slow, slow despite those GHzs. If I were to guess, it's a Socket 478 motherboard.
If you were to upgrade the RAM, a good deal of the delays will be removed, but for intensive tasks such as Google Maps or a flash video, the CPU will still stuggle. I've had a experience with a 2.53 GHz Celeron D, so I know the pain of computing on a Celeron D.
Before you crack open the case, there are a couple bits of software you can use to look at your system: CPU-Z.
CPU-Z handy tool will give you info on the CPU, RAM , and a couple other things about your comp. You can post screenshots of a program window by using Alt+Print Screen and saving the image using Paint if you want.