Right click and click on Open.
Alternatively, Click on Start menu, and click on Run (or Simply, Press the Windows Key and 'R' )
In the dialog box, type the drive letter, followed by colon (: ) and press enter.
Eg.
H:
then press Enter.
This way you will be able to access your disk. It is definitely a virus, and I had written an article about it once.. can't seem to find it now.
Abhas added 2 Minutes and 38 Seconds later...
Basically what is happening is, When you double click on the drive, it 'autoruns' a preset command, which is pointing to a certain script (might be harmless, but nevertheless, it's called a virus).
Scan your computer with the Latest antivirus, and also scan the removable drives.
Abhas added 14 Minutes and 4 Seconds later...
To solve this problem, you can try this tool :
"Open With" dialog appears when double clicking on a mapped network drive in My Computer