Questions about Mobo/cpu/ram FSB's Upgrading system?

I don't recommend socket 775 at all.

go up to 1156 and an i5-750 or go to an amd AM3 chip

What hardware is currently in the computer?

Current:
-Pentium 4 - 3.0GHz (not overclocked)
-ASUS P5S800-VM
-1GB DDR400 RAM
-ATi Radeon AGP card (forgot the model) 128MB
-500GB SATA hdd

Yea the reason behind the upgrade is that I think the motherboard is dead. because i cannot get it to post, no beeps no display. Just fans spin. I have tested PSU, all fine. I have done all diagnosing, reseating memory, taking out gfx. etc

So Yeah.

Hmm.. ok. I'd still either go for a 1156 platform or AM3.

What budget are you on and what're you using this for (gaming, photoshop, general use etc)?

To answer your earlier questions:

1) Using the correct settings You can natively use 1333 on 1156 and AM3 afaik, I'm not sure the limits on 775

2) I thought I knew the answer to that.. but then looking at what you've said I don't actually know. sorry bout that.
Ed: I think this is the ratio between FSB and bus speed.. mb? lol I'm just having guesses here.

3) Bus speed doesn't really matter in CPU speed if the total speed is still high. bus speed is just one of the things that, when put together, make up the CPU frequency.

4) Not really sure on that...

Anywho.. answer and first set of questions and we'll go from there.

Since i'll be using my old case, hdd, monitor etc. Ill only need to get the cpu, mobo, ram. My brother will mostly be using it for causual things such as email, internet, watching movies and Photoshop.

ok, a casual computer. What's your budget?

i guess around 500 or lower, since i dont need to get other parts, just cpu, mobo, ram.

Hmm. I'm thinking an Athlon X3 build. What about you Mr/Miss Squirrel?

sounds about right. MAYBE an SSD for faster OS boot since no HDD/Monitor/Case.

Let me stretch my newegg legs. I'm thinking an 880 Mobo, an X3 or x4 Athlon II, 4 GB of RAM, a new PSU (400W-ish) just because of the age of the PSU in the P4, and maybe a low-end graphics card

yes. here's a build:

AMD Athlon II X4 640 (3.0 GHz) Plus Gigabite 770 motherboard with 2 USB 3.0 ports: $162.98 + $10 MIR
http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...
the motherboard doesn't have SATA 3 (but you won't be using it), but does have 2 USB 3.0 ports for future needs.

Mushkin Enhanced Callisto Deluxe 40 GB SDD: $99.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
40 GB is enough for an OS boot and several applications you use all the time. Mushkin Callisto uses the newest Sandforce 1200 controller for maximum lifetime out of your disk.

Mushkin Essentials DDR3-1333 4 GB: $66.99 + $10MIR
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Basic DDR3 RAM, cheap, yet from a reliable brand. Its hard to argue with this price.

Xigmatek PC-402 400W 80+ Bronze Power Supply. $39.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
This was reviewed a couple weeks ago, and managed something like 645 or 685W at peak power. It is probably the exact same parts as the 600W version

EVGA GTS 450 1 GB Video card: $129.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I picked this because it had free shipping. There is a gigabyte that's the same price with a $20 rebate, but it was $8.00 shipping. This card is nicely factory overclocked too. As it is, it will handle any game thrown at it at resolutions up to 1600x900.

total cost: $499.94 with $20 in MIR, and $11.49 shipping.

Wow. Thanks alot guys. im going to take this into consideration seriously. Thanks again both of you!