Many time many of us have faced this problem that on double clicking the drives they don't open instead it will ask to "open with" ..
its happening because your system is affected with some virus which has created autorun.inf file in your drives.
1)Open the task manager and see the process tab and try to identify the unknown process and click on end task after selecting it
or process explorer from microsoft might help u
2)Delete its entry from startup too..
[registry startup also]
3)start>run>then type cmd and press enter
type the following commands
4)C:\Documents and Settings\a>cd\ press enter
5)C:\attrib -s -h -r autorun.inf
7)C:\D: (repeat these commands for each drive you have)