If you really want to speedup your windows 7 installed PC, you can use Readyboost feature of windows7.
readyboost is a service that help operating system ,to use a flash usb as a ram(Random Access Memmory).

Here is the simple steps to follow if you decided to setting up readyboost now.

Plug IN your Flash  USB.



Open My computer,


Select properties of the usb flash drive,


As in the above picture, select Tab 'ReadyBoost'

Select Use this Device Option.

Assign Space you reserve for System Speed.

and press Ok.

You are done!

If it says, current hardware doesnot support,

Try
Backuping any files that exist in usb drive, and do a full format. when formatting, set options as ,Filesystem:NTFS, Allocation unit Size:Default allocation size. and untick Quick format.


Click on start, after Appearing 'Formating complete' dialogue box, try repeating the first step !

To Unboost, right click the usb flash drive in my computer, and select Eject.