• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 842
  • Last Modified:

Drive letter designation (C:) on my primary partition has been lost

My system will not boot.  It gets as far as the Windows XP logo with the 'busy bar' going back and forth, hangs for a while, and then reiterates the entire reboot process.  Starting in Safe Mode reveals a hang at MUP.DLL.  

I booted Partition Magic from a bootable CD and discovered that the primary partition has no drive letter allocated to it.  Running FDISK shows the same problem, but I can't seem to do anything about it.  I tried PQBOOT, too.  (There is also a small partition which is described as FREESPACE.  It has no drive letter either)

How can I restore drive letter C without erasing the entire operating system?
2 Solutions
Safe mode normally takes ages to load the MUP.SYS file (is it definately DLL file, or SYS?). If you leave it to load it should eventually load into safe mode.

Once in there, right mouse click on the my computer icon and click "Manage" to load the computer management MMC. Click on "Storage\Disk Management", Right mouse click on 'Disk0' and select "Change drive letter and paths..."

This will allow you to reassign the drive letter to the partition.
There are 2 possible issues I can think of:

1. you might have been infected by a virus and this damaged some parts of your operating system or even changed the partition table, so you have the 'no C:\ letter' problem. In such case, I don't think you can just restore the C drive letter. You would probably have to reinstall the whole operating system.
You might also try to plug your hard drive to another computer that has a working OS (and some good antivirus on it) and see what happens. If that OS can recognize your drive, you can copy any files that you need from the Windows folder and perform new installation on your own computer.

2. the other option is that your hard drive is damaged. In such case, I'd also try to plug the hard drive to another computer (with working operating system and some antivirus installed) and check if that computer can see the drive. If so, I'd copy as much data from the drive as possible and buy a new drive. You might be able to mirror those parts of your damaged disk that work and restore them to a new drive, althought, I don't know any applications that can do it.
Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

the mup.sys problem can be caused by nearly everything, hard and soft.
you can disconnect all devices and cards not needed for booting, and test.
bigdudAuthor Commented:
Thanks for your quick responses, guys.  I have an update:

1. Sorry, I meant MUP.SYS, not DLL.  

2. Even in safe mode, after a half minute or so, the delay at MUP.SYS falls thru and the entire boot process reiterates.  So I cannot get into the operating system under any circumstances.

3.  This is a laptop, and I cannot try the drive in another computer.

I'm inclined to agree with CyberGhost,  and looking forward to reinstalling the operating system.
Any final suggestions?
try a repair install :  
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Upgrade your Question Security!

Your question, your audience. Choose who sees your identity—and your question—with question security.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now