Mid 2009 Macbook Air Problems and Questions

Hello,

I have a Mid 2009 Macbook Air, 1.86 Core 2 Duo 120gb Sata drive, 2gb ram with Snow Leopard currently installed on it. I am hoping to get some answers and confirm my suspicions of what might be wrong with the laptop, as well as solutions for fixing it.

What I do know from my brother in law who had this previously, is that he is not that computer literate. It's very possible he installed some type of malware or something, all I know if that there was something that was continuously asking to purchase the premium version of a virus or protection program. I don't remember the name because I tried to remove it some months ago. None the less the computer has been working very slow, takes a long time to boot up (5 minutes or more, usually closer to 10) and it has a hard time doing more than one task. My suspicions are that the hard drive might be bad (he didn't take great care of this so I assume it's been dropped a few times also, it's a little beat up).

When I've tried to run Disk Utility, it basically freezes up. I'm not sure how else I might be able to check the status of the hard drive. Additionally the usb port on the side does not work. So my questions are, how can I find out if the hard drive needs to be replaced (and if it does, where is the best place to buy a replacement or possibly upgrade to a SSD). And is there a way to troubleshoot the USB port? I'm willing to take this thing apart to check the connection, or is it likely that the port needs to be replaced? If so a good place to buy a replacement would be appreciated.

Any help would be great!

Thanks!