Got the laptop from my buddy and said it works fine until I plugged it in all i get was no operating system found. So I bought a new hard drive and the same thing. No operating system found. I'm totally new at the computer thing all ready $300into it and no idea what to do next
OK. That is scenario #2 in the list I made.... If you paid your "buddy" much, then you are getting hosed. If you paid more than $100 for the replacement disk drive you paid more than necessary....
BUT to your problem... The disk drive you bought doesn't have an operating system on it. Since this was from a "buddy" you probably didn't get a recovery DVD or an operating system DVD. If this is a major brand laptop your "buddy" (assuming he is the original registered owner) could get a recovery DVD from the manufacturer for a few $$$. That would allow you to install everything on the new disk drive you bought.
Failing getting a recovery disk from the manufacturer, you will have to do it the hard way. That means getting an original Windows DVD and installing from that. The sticker on the bottom of the laptop will tell you what version of Windows the vendor shipped it with. You will then have to use another computer to get all the drivers from the manufacturer's website.