Install Windows XP on Compaq Presario CQ40-115au
Use XP SP2 only, most of XP drivers were built based on XP-SP2.
If you don't have XP with SP 2,get it first:
Use Nlite to sliptream ICH9 sata driver.
A good guide to guide sliptream sata driver
here: (but do not use the ahci provided by the webpage download the aahci driver below)
ICH9 sata driver, the driver is located in iaAHCI.inf and is called ICH9M-E/M SATA AHCI Controller