After many hours of googeling around the web I found a sugestion on my SSD-disk-manefacturers homepage saying that I should update my SATA-Controll drivers for my motherboard. I'm not sure this is a solution to your problem, but I haven't had any problems since I did that. Like I said before, I'm not a computer wiz, so I don't know what that did to my computer, but I haven't had any problems since (still just 5 cold starts since I updated it... *fingers crossed*)
Good luck.
Ill give it a go, although finding drivers for this PC is a complete pain.
I tried updating the BIOS but the updater from teh VAIO website doesnt work, and its posted on their forums by a lot of people, but sony doesnt seem to give a **** about it.
I ALSO JUST FOUND THIS POSSIBLE SOLUTION EXCEPT I CANT UPDATE MY BIOS
Just posting the details of a problem I had and the solution I eventually found in case anyone else suffers the same issue in the future.
The problem I had is that my onboard Intel Matrix Storage Manager RAID Controller would not recognise my new OCZ Vertex 2 when SATA mode was set to RAID in BIOS, due to outdated ICH9R firmware. It turns out that the firmware version I had (ICH9R 7.5.0.1017) suffers from a range of compatibility issues with SSDs which can cause delays or failures in detecting the disks. However, since the controller is onboard, its firmware can only be updated with a BIOS update.
So, if you have a motherboard with an ICH9R Raid Controller and are having problems with SSDs, all you need to do is find an appropriate BIOS update on your motherboard manufacturer's website which upgrades the ICH9R firmware.
Unfortunately there is no official update for my board (Asus P5E3 Premium Wifi-AP @n). However, I eventually found a user on the Asus forums, John47, who has created a custom BIOS for this motherboard which combines the latest official Asus release (0803) with the latest ICH9R firmware (8.9.0.1023). This BIOS update has resolved my problem perfectly.
So that other people can access the custom BIOS, I have uploaded it here: http://www.mediafire.com/?s6i4d1bzxh54hmq
It goes without saying that this unofficial BIOS is not supported by Asus, its creator John47, me or anyone else - you use it at your own risk. However, for what it is worth, I can say from my own experience that it worked perfectly for me and has resolved all my issues.