Uh-oh. In that case, I think I may have made a terrible mistake. The following will be my attempt to accurately illustrate my actions since purchasing my first few BTC earlier this year.
After buying about 5 BTC from localbitcoin.com, I borrowed a laptop in order to make my own wallet and store it on a flash drive, since I don't own a computer. The bitcoin-qt client was downloaded to the laptop, synced, and I sent my BTC to that wallet. Then I copied the qt client to my flash drive, 'backed up' the wallet.dat file - saved it in another folder on the same flash drive and named it "CHEESE.dat" (don't ask why). Please note that I didn't know about any info stored inside of %appdata% - or that it even existed (which is stupid of me if you look at my post history). I haven't made any transactions since that time. That laptop I borrowed has since been returned and wiped.
In summary, I have the bitcoin-qt client along with my CHEESE.dat file on a flash drive, and I have synced the qt client on other computers and tried replacing the wallet in %appdata% with my CHEESE.dat file (I renamed it wallet.dat once I moved it into %appdata%) - still 0 BTC. Is there any hope to recover the lost BTC?
Thank you for your help in advance.
P.S. I am planning on buying a laptop in the near future to avoid this problem.
When you look in the "Receive" section of Bitcoin-Qt, you'll see your addresses there. Do you see the address that you sent the 5 BTC to? If not, then you either made an error when you tried to copy wallet.dat into %appdata% or you made an error when you tried to create a backup of wallet.dat to CHEESE.dat.
The naming of the wallet file is specific. It is likely that it won't work if you accidentally named it "WALLET.DAT", or "Wallet.dat", or "wallet.dat.txt", or any other variation. Take a look in the %appdata% directory. Make sure you only have one file in that directory named wallet.dat and that it is all lower case with nothing else in the filename.
If you see the address that you expect in the "Receive" section of Bitcoin-Qt, then it is possible that you need to start up Bitcoin-Qt with the rescan command line parameter.