It will help us a lot if you provide your system configuration including your motherboard, processor, memory and power supply.
From the information that you provided, the motherboard temperature seems to be wrong, if it is reading it like -1 then it could be a short on the system and taking the motherboard out of the chassis will be the first thing to try.
Motherboard: INTEL DG41RQ_
Processor: Intel E7500 2.93GHZ Core 2 Duo
Memory: 2gb Kingmax DDR2 667MHZ, 2gb Strontium DDR2 667MHZ = 4gb
Power Supply:HKC 500W ATX
Hard Drive: 250GB Seagate 7200RPM SATA
Graphics Card: 1gb Nvidia Geforece 9500GT
when i bought the motherboard it is bundled with processor. now thats the spec of my desktop and now i try to open my computer then "Hardware Monitoring" in Bios i found that my mobo temp is back to 30C again it's now normal but it wont complete shutdown. please help me victor thanks.