300 coins? If you're serious, that's worth $2.4 Million dollars today. And more importantly, it makes me your new best friend!
Go over all of your notes and find out how you were paid. Most probably, you were paid directly to your own bitcoin wallet. If thats the case, those coins are still in that wallet, and still on that computer. Hopefully, you still have both, and haven't reformatted your hard disk.
Look around for the bitcoin wallet software you had, for example, Multibit. Load up the program and enter your password. If you don't remember your password, you will need to restore it but doing so is tough. If it uses the Lighthouse BIP32 format, you would have written down a series of words like Home, Train, Orange, Car, and about 12 other words in a certain order. You would need these words to restore your wallet but of course this depends on the wallet you used.
Good luck! And yes, you CAN buy me a Tesla Model S, my new friend!