Laptop Problem

This is my very first post so I’m sorry if this isn’t the right place to ask for this. Somehow I managed to get a used Sony Vaio with a problem in its HD connection. The problem isn’t in the HD itself, it’s in motherboard socket (I don’t know how to name it) for the disk. The disk was previously changed, thinking the problem was on it but the problem continued. I guess the problem is on the motherboard and can’t think a way to fix it, so I thought a number of possible solutions and ask for advice (or, if you guys can think a way to fix it without spending a lot of bucks, welcome). The solutions which came to my mind were:
1st buy a sony vaio disk bay for the multipurpose slot, and use the HD I already have. The main problem with this is the money I have to spend.
2nd buy a USB adapter for the disk and boot from there. The main problem is that de notebook can’t boot from usb natively, so I must look for a way to do it (maybe with a DOS diskette with the properly drivers)
3rd booting from lan. The problem is that I don’t want to do this fool thing, and lose all the hardware the vaio has ('cause I won’t be able to use it).
I know of the problem because of the S.M.A.R.T. alert I get each time I run the pc, and because every time I manage to recover the system (with the Sony VAIO System Recovery discs) and reboot the system, it brokes. Also, the OS installers sometimes can see the disk and sometimes they can’t.
I think that’s all.