Ok so I am running a PC for gaming and I am having overheating issues.
here is my system setup.

Intel P4 3.0GHz HT
Heatsink/fan running at 2600-3500 rpm
AGP gpu ATI HD 2600XT iceQ II
4Gb of Patriot ram 400Mhz
160Gb HD
2x 120mm fans (case)

Ok so here is the thing, right as I turn it on and it idles I notice with speedfan it is running 49-51c temp, and thats freakn hot, and I have messed with the motherboard settings to decrease voltage in the ram,sped up the fans a bit, and nothing seems to help, I am wondering if it is possible that the heatsink and fan needs to be replaced and if so I am having the up most difficulty finding a fan and heatsink that can handle a gaming experience for a socket 478, I mean I dont want to have built this machine and only be able to use it 10 to 15 minutes at a time.

So can someone help me out when it comes to cooling this thing, I am shooting for 40c idle temp or less, I know that seems impossible, but hey I HAVE A DREAM.

Let me know your advice.

The temps you are describing don't seem that hot at all.

You own a Pentium 4 dude, one of the most power hungry, heat generating, BBQ grill CPUs ever made.

Thats average temps, nothing to worry about, as long as the hsf is clean and the thermal paste is in tact etc.

Ok I didnt know that the P4 actually ran that hot then, I am using speed fan and the little animation near the temperature shows a flame, and the PC actually reboots itself whici is really weird, I got a temp rating right before I turning it off at 60c, So I had bought a new heatsink and fan from tigerdirect.com its a thermaltake and new thermal compound as well.
I should be getting those in along with a KVM switch I ordered. if it runs better Iw ill let you all know.

Ok so I was playing a game earlier and it crashed, however I think it was due to the fact that I am using a no-cd crack and its a bit unstable. However when I ran windows media player and started ripping music to my pc it rebooted the computer in the middle of what I was doing.
O did what some one suggested which was update the bios, drivers, and such and it still did it, twice, so now im stuck, im thinking it is running to hot still or its just very unstable, and I wouldnt understand how that would be caused since its a fresh copy of XP and its not under a huge load.
So now I am definitely stuck, and in need of help.
Keep in mind I have a brand new heatsink and fan on the way with new thermal compound since the original heatsink/fan is about 4 years old.

Enter your bios and load the defaults and try that, also set that shutdown temp to 70*c, also make sure your system is clean and no dust blocking the heatsink

cheap psu's and motherboards give up like that, aswell as cheap ram etc - check for faulty capacitors on the mainboard etc.

btw list your specs - PSU, motherboard, ram, etc

My advise is to replace that antique P4 and build a new system.
You don't have to get rid of it though.It might be fine for older games.
Just realize that it's worth a little over $100.My brother several months ago gave me 10 P4 systems and I sold a few of them for extra cash to build a newer system.

mOBO: INTEL D865GLC
GPU: ATI HD 2600 iceQ XT agp
RAM: 4Gb patriot with heat dispursment shields
PSU: NZXT 600W
CPU: INTEL P4 HT 3.0Ghz

I still have my old P4 northy running, which is 3.0 HT.

If you wanna spend some cash, you could get:

Zalman 7700

or perhaps:

Thermaltake CL-P0114

That big piece of copper will help more on CPU loads then the stock HSF.

Depending on how cool the ambient temps were, (as well as PC case airflow), the Zalman 7700 on my system would idle 38-44C.. loads would get 48-57C.