i was playing mafia then i noticed my pc was louder and i looked at the back and the powersupply fan was throwing more air out than before is this normal there was more air coming out the powersupply fan

Does your PSU have a sensor that will make the PSU increase it's rmp when the temps go up? Intel P4 3.2E Ghz@ 3.8Ghz Asus P4P800-E Deluxe Kingston 2GB PC3200 D-Channel Asus AX800 Pro w/Zalman ZM80D-HP WD Caviar 160 GB WD Raptor 37 GB Zalman Reserator 1

Yes, it is normal! You may have a variable speed fan on your PSU. Most of the newer PSU came with this type of fan. Whem the air temperature raises, like whem you´re playing mafia - cpu get hotter, video get hotter too... All the air inside the case get hotter and the PSU will have cooling problems. A hot PSU will not supply teh correct power specified. It needs to rises the airflow to compensate the hot air that is getting inside it. What is the model of your PSU? I´m just curious... I want to get a good one like seventeam or sunflower with low noise levels, real 400W power, sata support and active pfc. Anyone knows cheap and good alternatives to the sunflower and seventeam ones?

my computer is old now its only 350 watt powersupply it has a geforce 2 with 64 mb ram on graphics and 256 ram computer memory pentium 4 1.6 GHZ hardrive 40gb

It is not too old to me! Except by your PSU, everything in your computer is better than on my one. Curious this thing... You probably own your CPU has 3 or 4 years, isn´t it? And only now your see difference in the airflow? May your PSU have no rpm adjustments... How is the noise you hear? It is only a more intense fan sound? It is some strange sound like if it is vibrating a bit? Two hipotesis: (only consider this if you don´t have a variable rpm fan on your PSU - search for the model and supplier of your PSU on google to get the information) first - the fan simple speed-up second - the fan is vibrating and will stop to work sometime. If you got some extra vibration, you can buy a new 80mm fan and replace the old one because it get too old. If you got only better airflow, without any modification on your PSU or case, you must check the voltages of your PSU. The speed control of the fans are generaly made with voltage adjustments. If your PSU is several years old, it may be near to stop working and may cause a over-voltage. Some mobo sensors softwares can tell you what is getting out from your PSU in the 12V, 5V, 3.3V and Vcore lines... The normal is to get voltages in a +- 10% deviation. 12V + 10% = 13.2V. Anything higher than this may toast your mobo. Whem you find this type of behaviour on your PC, after several years without notice of it, you are certainly running into problems. Check the voltages and check the fan by security! All of us have too much to learn, but with some luck we can even help someone.

my psu does not have a variable rpm ajustmant i can hear it speed up will this be dangrous if i leave it to long will the fan burn out

Ok! I think the best thing to do is to check the voltages of your PSU. Try to use the software I said you, like Hardware Sensors Monitor, and preferably try to check with a multimeter... I can´t help on this test, but openning a new post about measuring voltages with multimeter can help avoid problems and mistakes. If the problem is not a bad fan, may your PSU need repair or replacement. Better to look at this in the place of kill your mobo, right? Hope this helps! All of us have too much to learn, but with some luck we can even help someone.