"My multimeter shows..."

DON'T use a multimeter but use an oscilloscope!!! Most phenomena on a microprocessor circuit are much and much to fast to be measured with a multimeter. Use an oscilloscope to see if there is a clock, if the reset pin is actually doing what you expect, if the power supply is not grossly polluted etc. You can even watch MOSI and MISO during program transfer to see if there is any traffic at all.
If you do not have an oscilloscope, and you are serious about building circuits, get one in a hurry!