I have not gotten a chance to experiment with Windows 8 lately but:
1. Hit the Windows key + Q to bring up the App search.
2. Search for "My Computer. From here you can access your flash-drive and CD/DVD.
NOTE- With Windows 8 you can Enable/Disable the auto play feature. [The selection screen that gives you the option of what you want to do with the files/media on the cd/dvd/flashdrive.]
Check to see if the auto play feature accidently got disabled by these steps.
1. Windows key + Q and search "Control Panel"
2. Clcik "Hardware and Sound"
3. Click the "Auto Play" Option and there is a box in the top left that says "Use Auto play for all media and devices" Make sure that box is checked and apply changes and try your flash drive again.
PS. Sorry I was a little busy I didnt see your post about this issue. Hope this fixes your issue.