A handy solution to "USB device not detected"

Problem:
This is a very common problem people face while using their pen drive with the computer. A most common problem with students as well as professionals :

• Windows XP does not recognize USB Mass Storage Drives OR
•  Device is detected and listed with an exclamation mark in Device Manager

After a lot of experiments, this is what I found to be most accurate and simple steps to resolve this with a sure shot. Hope you all will find this useful

Solution:
Please follow these steps to get rid of this problem :

1. Delete following file: C:\Windows\inf\infcache.1

2. Go to windows\inf folder and see if you have read/write permissions for following files:

• usbstor.inf
• usbstor.pnf

If not, open security settings for above files and add your username for read/write access.

3. Open registry editor and delete following keys:
HKLM\System\CurrentControlSet\Enum\USB\ <read all keys and delete all those saying USB Mass Storage Driver>

Add following keys:
HKLM\System\CurrentControlSet\Services\Usb. Add a new DWoRD Value and name it "DisableSelectiveSuspend". Give it value 1

4. Make sure you have USBSTOR.SYS file in your windows\system32\drivers folder. If it is not there google it and download it and place it at the said location.

If your problem still persists (there are very few chances), then post your exact problem. :)