Need SERIOUS help on upgrading computer parts!

Well Im a new forumer so forgive me if I posted in the wrong section.

Is my computer still upgradeable? I bought it in late 2006.
Its a Dell Dimension E520.

If yes, read on. If no, then ignore the rest of the thread.
Hm yeah. My computer cant run most games like Crysis smoothly anymore.

So I've decided to upgrade it. Its my first time doing so.
Some specs of my com. If you need more, dont hesistate to ask.

Processor: Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz (2 CPUs)
Memory: 1022MB RAM
Video Card: Radeon X1300/X1550 Series

I've got about $480 to spend and Im from Singapore.
So yeah, what would you recommend?
I just want to run most games smoothly and dont wish to spend too much.
I dont need a monster, but if its achievable with that budget, I dont mind.

The main things I hope to upgrade are
the CPU speed
the system RAM
and the Video Card.


On a side note:
Is the RAM = the computer speed? I seriously have to upgrade my com's speed. Its taking like 10mins just to power up or shut down.
If not, then what determines the computer's speed?

And is the processor upgradeable? Its got me wondering for some time.

I hope that at least someone would give some advice.
I posted on other forums and no one replied me.
Please. All help is appreciated.

Well one thing I can tell you is dell computers are a pain when trying to add aftermarket parts, If i was you i would upgrade your ram to at least 8 gigs, which will run you around $90 from newegg, http://www.newegg.com/Product/Produc...82E16820231151 the next thing I would do is that video card, you can get http://www.newegg.com/Product/Produc...82E16814500080 for about $120, now the big issue with dell is that they come stock with very weak power supplies. It would probly be safe to say the one in your machine now can't handle just these 2 minor upgrades. This becomes a bigger issue because the dell motherboard chipset usually freaks out when adding a "non-dell" power supply, I.E. i tried to put a corsair 500w in a dell optiplex, not only did the case not have standard mounts so it wouldnt sit in it right, but when trying to boot it would lockup at the boot screen everytime. Not sure how to correct this, since the 2 upgrades mentioned above were about half your budget I would contact dell or try and google compatible power supplies for dell and try and grab an aftermarket power supply of 500 watts or better. Corsair and zalman both make great power supplies if you can find out what you have to do to get a dell to accept them. With that ram, video card, and power supply you will definatley notice heavy performance increases 8) .