Sorry to make you confusion.
I mean in general the XP PCs had been replaced by the WIn7 PCs when we did DTR.
Only some XP PCs are still used due to those XP PCs connect to the Plant machinery and equipment in production or R&T areas. And those XP PCs are stand-alone version.
The reason why those PCs are still using XP because the software which we use to control the machinery or equipment are windows XP based. Some software will required the high upgrade costs if we'd like to change to Win7 so we leave it as it were until the suitable time of changing.