Any Ideas would be appreciated - I have an older Sony (Dec 2003) with Northwood 3 Gb processor W/HT Running XP Pro – I just replaces the Hdd two years ago with a WD 7K 16M ATA100 WD5000AAKB 500 - It has been running Pretty good, but yesterday when I rebooted I got a black screen that says at the bottom "Primary master hard disk error, and to press F2 – when I do it just says Wait… and nothing happens – So I powered it of and rebooted while holding down the F2 key to get into the CMOS setup – I got in and everything looked normal – I exited without saving the settings and windows XP booted normally – The BIOS chip is still keeping Time and Date so I don't think it's the battery, but not sure – When Windows started I ran a deep analysis with IOLO System Mechanic and it just found some system clutter (as normal) No Hard drive errors. – Anyway this is now happening every time I reboot, and it happened once while in hibernation, so I turned hibernation off – I'm afraid one of these times it won't be able to recover. - Any Ideas would be appreciated.