Wow!!!
U sure do got infected by some virus
Scan ur PC.................and to open those drives right click and select Open, got to Folder options and mark view hidden files and mark view system files too.
When double clicking upon drives opening a MS-Dos windows means, theres sure an autorun file which is causing the problem.
If my diagnosis is verified by u, I'll tell u wat to do next.
u can refer this
thread