Thanks for the suggestions chaps and ill consider a longer term solution of going Netbook as previously discussed here.
 
 This does have added complications as the present problematic AC power tower is supplying command and control for a number of serial drivers and well as the normal USB's. I do get a little QRM from the USB side as well and that why Ive gone for opto isolated true serial ports - not a whisper of common mode noise with them.
 
So my short term need, simply, as Ill have to get my son to install, is a pure plug and play clean UPS - until I get get home in a a few months and rebuild using a new PC perhaps. This goes together with the 150 amp per phase AC/RF filter from "Filter Concepts"  http://www.filterconcepts.com/three_phase/3x_series.html work as well to be completed
 
Laurence KL7UK remotely dumping from Oklahoma. Isnt coffee wonderful for jet lag...