Problems with Vaio machine booting

Has anyone had any major problems with the Sony Vaio Z series ultabook? I bought this computer for my business needs but after only one month it refused to boot and I had to go and get it completely reinstalled. The service centre in Brisbane said that this was due to the OS system. 11 months from that time I have had the same problem again it refuses to boot and you cannot even access the data - Brisbane service centre once again has claimed that there is absolutely nothing wrong with the machine but the problem is that it is not compatible with the OS system - Windows 7.

Both times the machine has failed so badly that it cannot even boot to a position where another IT person can get do a dos platform or other to access the harddrive - this is quite a problem.

I am very disappointed with the computer and with the Sony Support system centre who will not even discuss the potential that there may be something wrong with a machine that crashes so critically twice in such a short period of time - or given any better advice. The machine has proved totally unreliable and Sony products not suitable for business purposes as you need reliability and are likely to be running Microsoft products on it.

I have seen in another forum that this seems to be a common problem with the Z series ultrabook - always pays to research before you buy! Unfortunately I cannot afford to get rid of it yet as it is only one year old, so need to run for another 6 months or so - if others have had similar problems would you be able to advise what sort of OS system is compatible and how can I improve the reliability of this SSD machine so that it does not have this failure again at least in the next few months.