my laptop wouldnt start saying there was an error with system 32, i tried using the recovery disc but had no admin password so couldnt use it, then when i tried to restart again it just worked?? and its workin fine? how has this happened?

What's the actual error?

It just came on a black screen on start up saying error or missing system32, use recovery disc and press r to repair

Ah, possibly a knackered hard drive :(

system32 isnt a file, it is a folder full of files - filkes that are vital to the operating system. If it happens again it probaly does mean your drive is not spinning up to speed correctly, or the read heads are going out of alignment and so you will need to replace it; but even before then, take it as a warning, and make sure you have anything important backed up to another drive or external device (USB drive, SD card etc)

So is there Anythin I can do to prevent it happening again? What causes it on the first place?

Unfortunately things that affect us all - Age & wear.

The platters & drive motor only have a finite lifespan. If the drive has had a busy life (read & written a lot of files) then usually 3-4 years before they start to get a bit shaky.

I've also read somewhere that SSD drives have a theoretical 5 year lifespan.. that said the test was at between 10-20 x the load of a conventional one.