I would say you need thermal paste and clean the dust from inside your computer.And while you are at it give it an overhaul download some Free antivirus and BSOD Bluescreen of death can be caused by a number of things If the PSU power supply units fan is not working the PSU is faulty
http://pcsupport.about.com/od/toolsofthetrade/f/powersupplytest.htm A bad or faulty motherboard data lead or its connection if its a flat 40 pin ide it will be the first to fail make sure all leads have a dust free secure connections A bad driver loose or faulty lead or not having enough ram or the RAM modules might be dirty. Might be getting hot Check you CPU make sure its securely seated and has thermal grease
http://www.hardwaresecrets.com/article/Thermal-Compound-Roundup-February-2012/1490 Remove the memory modules from their slots.
Take the opportunity to clean the slots on the motherboards and the memory module connectors. Use compressed air to blow dust away and clean contacts with a soft cloth. Do not use a metallic vacuum cleaner if it touches any component it may create a short and cause damage to the motherboard or other components. Then reseat the modules. You should hear an audible click when they are in place. Do not use too much force to reseat the memory module in to the slot this can cause damage to the module, slot or motherboard. You might not have enough RAM random access memory not having enough will cause your computer to run over its maximum limits and can cause the blue screen of death and hang and cause memory dumps If you're not sure if a module is right for your system, use the
Crucial Memory Advisor tool for a list of guaranteed compatible modules. first you will need to select the manufacturer from a drop down list then select your product line from a drop down list then select the model then click find it will take you directly to compatible ram also you will have an option to scan your system you should always ask the seller if they guarantee the compatability of the ram before making any purchase if you dont want to install more ram uninstall some unnecessary programs make sure your ram modules have a dust free secure seating and the CPU central processing unit has thermal paste If eventually you can get a screen Click start control panel administration tools computer management device manager scroll through all of your devices if you see a yellow question or exclamation mark ? ! or a red X you will need to update the drivers for this device right click select update driver/reinstall driver. If you computer came with a motherboard disk the drivers could be on it
or you might have to download one. or it might be a virus right click in bottom toolbar select task manager applications to see what is running and processes to see what is ticking over. http://windows.microsoft.com/en-US/windows/products/security-essentials/product-information malware protection
http://100-downloads.com/download.php?p=615 windows xp microsoft security essentials
http://100-downloads.com/download.php?p=614 windows 7 microsoft security essentials Hope this helps.