I have this new computer:
It's a "brand", not custom built computer. It's made by IBM, and titled 8187 F4G.
Here are the specs:
http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-51126

Main parts overview:
Intel 865G chipset (same as 865P/PE + an Intel onboard graphics chip).
Pentium 4, 3.0 GHz, 800 MHz FSB, Northwood 130nm core (512kb L2 cache).
Some onboard audio.
Intel onboard LAN (10/100/1000 :)).
512mb 333MHz dual DDR (2x 256mb) made by IBM.
Western Digital 40GB 7200RPM IDE HD (Yes! Not a crappy IBM DeskStar HD!).
Some DVD-ROM.
Motherboard is micro-ATX, so has only 3 PCI ports, and one AGP 8x port, all of which are empty.
And... A 230W power supply for all of the above.

I am planning to add:
(Definitely) Western Digital 120GB 7200RPM SATA. (Without removing current HD.)
(Maybe) Radeon 9600 SE video card, doesn't matter much which manufacturer.
(Maybe) DVD +/- RW, haven't decided yet what type.

My concern is the power supply.
I was pretty surprised to see it came with only a 230W power supply for a P4 3.0GHz CPU...
I assume the lack of a kickass GPU is the blame for this.

Will that be good enough (especially for the extra HD, and maybe for the extra GPU)?
Or should I hurry up and buy a stronger PSU?

Edit: Forgot to add something that probably matters.
The monitor is connected directly to the wall, not to the computer's PSU.

Go Plextor on the DVD RW. Their quality is superior to most others, and they are ahead of everyone on engineering.

Don't get an OEM ATI Radeon. They have modified abilities usually specific to the motherboard it is paired with. Spend $20 extra dollars and go retail box ATI.

230W might be sufficient for what you had, until you add the Radeon video card, then you can forget it. Instant melt-down. It will generate lots of heat, and that power supply is unlikely to be able to provide the power and dissipate the heat.

Sounds like you already have the new computer. Too bad. Hostile has been paying attention to hardware again, and has some new advise, specifically regarding Alienware computers.

[quote] titled 8187 F4G.[/quote]

That made me laugh. :P

http://www.jscustompcs.com/power_supply/

[quote author=Grok link=board=2;threadid=7548;start=0#msg68312 date=1088874512]
Sounds like you already have the new computer. Too bad.
[/quote]
I got it for free. That can't be bad. I'm going to modify it until it suits me, and then I'll switch computers (still using the P3 450 right now). That'll definitely cost less than a new computer (especially note how much the CPU rocks).

[quote author=hismajesty[yL] link=board=2;threadid=7548;start=0#msg68314 date=1088875557]
[quote] titled 8187 F4G.[/quote]
That made me laugh. :P
[/quote]
Me too, at first. :) I'm used to it now.

[quote author=Thing link=board=2;threadid=7548;start=0#msg68317 date=1088876975]
http://www.jscustompcs.com/power_supply/
[/quote]Nice thingie (was down when I tried to access it, but the Google cache worked).
It said I need 400W for the PC + video card which I don't have + some random stuff I added to calculate an overhead.
I'll go with that and Grok's advice and replace the PSU, I suppose...

An idea I just came up with, that might save money:
The P3 I'm using now originally came with a 230W PSU, but it died and I replaced it with a new, P4-compatible 350W PSU.
So, maybe I can just swap the PSUs in these 2 computers? Put the new computer's 230W in the P3 case, and the 350W in the P4 case.

Will 350W be enough?

Depends on the brand of the PSU, and as Grok noted previously in another thread, the construct of the PSU.

If it's a decent quality PSU, most likely. Just don't try to kill it in its use.

However, you can get cheap Enermax psu's, $~100.

Enermax rocks. ;)