go to command prompt and enter in to the drive which is not opening in single click and then type attrib -r -h -s autorun.inf press enter and then type del autorun.inf then come out from the command prompt and restart the computer
for example if D drive is not opening go to D drive in the command prompt
d:\attrib -r -h -s autorun.inf then enter and then d:\del autorun.inf then restart the computer this command is applicable for win xp