no they wouldn't, they are set up so you can use them. i have done it. they wouldn't like you putting it on the hard drive but that is why you use a flash drive. and i will get some pics in a bit someone else is using the computer right now.[DOUBLEPOST=1362432690][/DOUBLEPOST]
also i should note that my local best buy, as it is in a rather small city might have 15 people in it at a time where as one where there might be 100 or more people in it at a time might have different rules and regulations.
Just went to the mall for a pretzel. Went into Best Buy and asked a sales associate. You are not allowed to install or download ANY program to their computers, at all, whatsoever. You aren't allowed to plug in your flash drive and run a game off of that. It a security risk to their computers to allow customers to do so. Also, the computers run "Display only" programs that block any and all installs. He told me it's a company wide policy. No exceptions, at all. If you've done this at your local Best Buy, they shouldn't have allowed it.
OP, while I was at Best Buy, I saw a computer, running a pretty crappy processor, with 4 GB of RAM for $300.
The 3 things to consider when deciding on a computer you will use for gaming: processor, graphics card/processor, RAM.
Edit: OP, please tell us your computer specs. Processor, amount of RAM and type of RAM (DDR2, DDR3, etc), what type of graphics you're using (integrated or card), what your OS is/bit type of your OS, what version of Java you're using/bit type of Java.