my athlon 2000+ is running at 79degrees celcius. when i boot the computer ssays there is a hardware error. when i enter bios and go to hardware, the cpu temp is in red and says 79 degrees. i have just installed a new psu and graphics card. cant think what it could be.
Assuming you have not disturbed the cpu and heatsink then either a fan is not working properly or you have one installed the wrong way round. The other alternative is that the graphics card and/or its cooling is faulty.
Can you change back to the old card and see what the temperature of the cpu is then? Anything up to about 60deg c is ok
If that sorts the problem then check for installation instructions of the graphics card. How is it cooled and is the cooling working properly?
Some modern graphics cards require healthy power supplies and churn out a lot of heat. The new psu could be faulty but this is unlikely. Can you feel the air flowing out of the back of the case where the psu is installed?
If the cpu is running at 79C, the fan is running at normal speed, you're certain that you haven't disturbed the heatsink seating on the CPU and the CPU formerly ran at a sensible temperature, then I can only think that the heatsink fins are blocked. Unscrew the fan from the heatsink and thoroughly clean any dust from between the fins. Clean the fan blades and refit the fan making sure that it is the same way round as before.