hello Davy, welcome to the vista forums,

arty:
unless your sisters machine is XP professional [not home] then the
built-in remote desktop in windows won't work,.
this would suggest you use a VNC type program to achieve the link, one
I use successfully is ultraVNC, which is totally free
'UltraVNC: Remote Support Software, Remote Support tool, Remote Desktop
Control, Remote Access Software, PC Remote Control'
(
http://www.uvnc.com/)
Others are available, just do a search for VNC freeware and you should
see plenty of response
You could also take a look at one of the online remote access providers
such as LogMeIn
https://secure.logmein.com/home.asp?lang=en
hope this helps
--
barman58
Regards,
*Nigel*
the beginning of knowledge is the discovery of something we do not
understand.,- frank herbert