OK, so installed up to PT LE 6.4cs9 on the system I first mentioned. At first it kept going to BSOD but then I updated PACE drivers as per this page at Digidesign:
http://www.digidesign.com/index.cfm?...0&itemid=23876
and it loaded ok. Opened some old sessions and everything played back ok. Have not recorded anything yet but will update when I do so.
Sean