I have a 4gb flash drive and I was trying to readyboost my comp with it to see if it made anything faster, but it came up with this error-

http://i230.photobucket.com/albums/ee21/Jello-Jigglers/doesnt.jpg

help? Do i need a new memory device? This one is brand new...

The flash drive has to have certain read/write speeds to be ready boost capable. Your's is apparently too slow. Link to the model?

Here are all of newegg's windows readyboost supported usb drives
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2013240522%201395528542&name=Yes
but imo the readyboost is not really that good unless your on a laptop where ram is really hard to upgrade.(or perhaps your crazy and you already have maxed ram and somehow want more )

ReadyBoost becomes less effective when you have more and more RAM. It's been shown to boot muchfaster for computers with 512MB of RAM, but the boost shrinks signifcantly with 1GB of RAM.

Haha well i have 3.5 gb i just wanted to give it a try lol, cause I run alot of high end programs at the same time, sometimes 3-5 really memory chewing programs(adobe CS3 suit, Autodesk 8 Inventor, iTunes, along with firefox and word processors and stuff.)

It won't make your programs run any faster, it'll help them load faster. Also, it's reccomended that you have 1-2 times the amount of flash memory than RAM. So if that reccomendation is actually a requirement, that would be the cause of your problem.