Killing computer virus & computer unwanted program in thumb drive by using cmd

During surviving in UTAR, I found that there are many computer virus & unwanted program inside UTAR computer CPU, especially computer in theater hall. So, all the student thumb drive are infected by either computer virus or computer unwanted program. Those computer virus are easily detected and remove by anti-virus software. However, the computer unwanted program is very hard to detect and remove from thumb drive. One of the example of computer unwanted program is autorun.inf file, which are always shown in hidden file. However, my house-mate, Ling Tek, student from Electrical & Electronics Engineering background, teaching me one way to remove this type of computer unwanted program. The following are the step for removing unwanted program in thumb drive:

1. Click "Start"
2. Click "run"
3. Type "cmd"
4. Then, click "ok"
5. Type drive name, eg. "C:" , then press enter
6. Type "autorun.inf", then press enter  
7. Type "del autorun.inf", then press enter

Step for opening the file inside cmd

1. type "dir/a/w"
2. type cd folder name
3. type del file name

The file is in the thumb drive, but cannot delete

1. type "attrib autorun.inf"
2. type "-s -h -r", press enter
3. type "del autorun.inf", press enter