Vista cancel data partition!!!!

I'm I little bit upset. After having created thru Vista HP procedure a partition for data, following MS suggestion, after 1 month I discovered that the disk was no longer available. I checked thru My PC, Manage, DisK management, that that partition was no longer formatted. All data were lost. I had this on two different PC .

I re formatted both, I tried to recover some files, now after more or less same time all is same: the partition disappeared again.

I know that this is a OS problem, but this behaviour never saw in the past is randomly affecting the PC. There is someone expalining ther behaviour?

I cannot have MS help being an OEM version.