HELP! I attempted to retrieve a very large file from my USB data stick and it was some how deleted.?

If its not on the memory stick where it was then you can download some memory stick data programs like data doctor memory stick recovery program and then search your memory stick to find whether it is there or not.there softwares are not free but you should download its trial version to check whether the file is still on the stick or not.if its there you should consider buying such software if the file is extremely important.there are also some free data recovery softwares but are not much usefull.however you should give them a try if you don't want to spend money.if you have checked using such software that the file is still there then you can take your pc to a local pc shop where the people can help you.

lookup "file recovery software" and done use the USB stick anymore until you recover the file.

If it's not on your USB stick and it's not where you were supposed to put it on your computer, then I'm afraid it's pretty much gone. Sorry!