Not entirely sure what you are asking but if your question relates to where to save the MVP (project) file then yes, as far as I know it can be saved anywhere, including a USB drive. On my computer all my video and project files are automatically saved to an external USB2 drive.
However, I think you need to try and determine why your computer crashes "again and again". Try to describe exactly what you are trying to do at the point when the crash occurs.
As Jeff says, projects (.MVP) files can be save to any media available to Windows including remote network drives. A much bigger issue, particularly if your computer seems unstable and is regularly crashing, is where (if ?) you are backing up your resources -- video clips, images and audio files. Note that Jeff said '...my video and project files...'.
MEP has several options under 'File' >> 'Backup copy' for this purpose. Storage is getting cheaper and cheaper; I recently invested in a 2T USB 3.0 drive for less than $100. Cheaper than lots of tears!
As cpc000cpc says the bigger issue is where you back up your media. You can save the project file to a thumb drive or USB drive but won't be able to play it or reload the project unless the media used to create the file can be found by the project file. If you want to be able to play the file, you need to export it, but then of course all of your edits are fixed and you won't be able to go back and change them.
Proper backup is one of the things that many people overlook until it is too late. I use 3 back up drives, 1 is connected to my system while I am working and does an incremental backup of my media files every time my computer is idle for more than 5 minutes, the next one is used to back up all media files about once a week, and the third is to back up my entire hard drive which I only do once a month but should do more often.
A far bigger problem for you right now is to figure out why your computer keeps crashing and take steps to resolve that problem because one day it will crash and not reboot, then you will be looking at trying to recover your files from the hard disc which is far more complex and time consuming than restoring from a backup. Some files may never be able to be recovered.
Thank you very much to all of you for helping me my problems.
As I am just like a beginner, I upgade my RAM and MEP MX to Magix movie edit Pro 2013 and I am wondreing if I could use such as Demo, Caption, Movie Template.... I have already installed in my PC with magix movie edit pro MX. Because when I download them the componants, it took me over 3 hours.
The three hour download would be a measure of the speed of your your internet connection and should have no bearing on the usability of the extra components.
When I only had a quite slow computer I still used MEP effectively -- just had to accept that previewing would not be smooth. I'd step through a complex transitions using the cursor keys to check for accuracy and export a tiny section to check for flow. The latest MEP 2013 (not sure about MX) has an option to render test sections and have them preview on the timeline seamlessly with simpler material. Best of both worlds!