Think I have solved it, have monitored CPU temp which is currently running at 76C, I know P4's tend to run hot but this I think is too hot, I think the CPU fan has somehow come adrift from the processor thereby showing increased heat. Motherboard is running at 51C which again is little high. To be on the safe side I am fitting new fan and heatsink which I hope will cure it.
Thanks for everbodies help and advice it is very much appreciated.