Loading Drivers Problems - XP - Mega2560

Using Arduino-0023 and every time I plug in Atmega2560 it finds it as new hardware and the installation fails spectacularly with either a freeze or a BSOD. Sometimes it takes out Windows and I have to do a System Restore. Once I had to rebuild XP on a new disk. I have a feeling that I have a driver resource clash with my USB keyboard. Anyone had similar and lived through it ? Windows 7 on my laptop runs fine and I loaded the environment and got the blink sketch running in minutes, but this is addling my ageing brain. Help is deffo needed. Ta Rob