Cannot boot XP as pc stops booting at Mup.sys - PLEASE HELP

miteshlad2003 used Ask the Experts™

I really really need some URGENT Help here..

My Windows XP Professional Pc has been working fine for over a year and now suddenly it

won't start!!!!.

I have tried going into safe mode and it hangs at Mup.Sys. It doesn't go any further and

reboots. When i try to go use the last good known menu option it starts to loads and then

suddenly reboots itself.

I have made no changes to the hardware.

*****   Things i have already tried:

tried the recovery console and disabled the mup service using the disable command.

tried disabling the serivce before that viaagp.sys ...still no luck

removed all my pci cards from the pc except my graphics card.....still no luck

disabled the usb options from my bios

i don't have a usb mouse

I have replaced the mup.sys file with the original file from the installation cd...still no


I cannot get the windows gui started at all...

I am now totally out of ideas and really need to get my pc working again....


Thanks for your time

Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®

When you tried disabling the MUP.sys driver did you use the command:


If so try:



If stil no joy,

How to Perform an In-Place Upgrade (Reinstallation) of Windows XP;EN-US;315341

HOW TO: Restore the Operating System to a Previous State in Windows XP;EN-US;306084

HOW TO: Start the System Restore Tool from a Command Prompt in Windows XP;EN-US;304449

How to Recover from a Corrupted Registry That Prevents Windows XP from Starting;EN-US;307545 

Do you have any networking devices on your PC, or even USB?
Remove these and see if it resolves the issue. If it does, then slowly replace the parts one by one to see what the failed hardware is. Replacing the Mup.sys driver usually wont help.
C++ 11 Fundamentals

This course will introduce you to C++ 11 and teach you about syntax fundamentals.

Scratch my whole comment as i am tired and missed that entire middle paragraph of your comment, sorry.
Just a quick question, is there any on board LAN?

I have seen this issue many a time with the mup.sys driver failing. 50% of the time I have resolved it with hardware troubleshooting, other times it has been a lot more difficult, even leading to reinstalling.
Try this link, if you have no luck from qfrens links:;EN-US;314079

Gemarti also has the right idea, you have to disable the MUP driver if you cant get passed it.

hmm i had a problem with XP yesterday almost similar to yours.
after putting in a new RAM DIMM xp booted as got to the logon screen...

delighted at my upgrade i quickly pressed the power off button instead of selecting @shut down@ from XP.
Q 6 hrs of hearache...after a reboot i cudnt get into safte mode or into xp
as the PC restarted anfter if gor passed "mup.sys" (in safemode)

i tested the ramw hich i knew was ok and gfx card..and hard disk.
i came to find out that xp was screwed! i had to reinstall it over xp

luckly it went well i got my pc back working but had to mess about with my own documents folders which i had made private (big mistake) but go every thing back..

so i guess all im saying recommed a reinstall..but make sure you know what your doing before you do so.
i believe as gfren, that a repair install is what you will need to do.
boot to xp cd, @ first blue install screen, select install.. it will run thru some config stuff.
@ 2nd blue install screen it will have picked up that xp is already installed and give you several options, the only option you need to be concerned with is REPAIR THE EXISTING COPY (R) make that selection and you should be on the road to recovery. you will not loose any of your data, however you will loose any non whql drivers you may be running and any and all ms hotfixes including sp1, unless your xp disk contains sp1.


thanks for the responses i am about to do the Repair.....

To the other guys, I have already tried stopping the service by issueing the disable mup command and also i do not have any LAN or usb cards installed on my pc....

could somebody please guarantee that all my existing software will continue to work.....or will it not......????

Would the repair blow away my old registry??? Should i back it up first??




Let me just clarify as i'm not going to proceed until i get this bit straight first....

On my pc i have around 5 user accounts and each person uses outlook xp will they lose all there data, contacts etc????...I have office.....will i need to re-install all my apps again???...

This is the most worrying issue for me and i don't wish to re-install all my apps......thats why i have asked above....should i backup up my registry.....and if so how can i do in the recovery mode i keep on getting access denied........


Mits (Very Worried!!)

the repair install will essentially reinstall windows xp without disrupting your installed programs and files. you will loose (not if you have them dnloaded and saved somewhere) any non whql driver you may be running and any and all microsoft hotfixes, including sp1, unless your xp disk contains sp1 (many oem's included this on their disks after sp1 was released) providing that there has been no major change in hardware of your system and that there are no hidden problems within existing software and the os, the repair install should go smoothly,  and fix your problem with the least headaches.


If u wanna Repair(resintallation), it is recommend u backup all the data and backup also ur registry.

HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and Windows Server 2003;EN-US;322756

and try to read this:

You May Lose Data or Program Settings After Reinstalling, Repairing, or Upgrading Windows XP;EN-US;312369

Data Loss May Occur After Reinstalling, Repairing, or Upgrading Windows XP;EN-US;312368



Thanks everyone for your help....

in the end i tried to perform a repair but never got the option and lost all my data......So i have got windows XP back up again and now i am having to re-install all my apps..

Thanks Again!


hi miteshlad2003 :
may i know y u accept  jman1980's comment as the answer?



Beacause he told me how to do it in a very straight forward manner withour refering to any knowledge bases.

apologies if I have annoyed you.


>>apologies if I have annoyed you
no ,u didnt.

>>..withour refering to any knowledge bases.
So that mean u didnt accept my comments as answer because i provided the links?


gfren, tell me how to split the points with you.

that would be fine. gfren did give the correct answer, just not in the context that the poster wanted, so, i think that would only be fair.


Thanks jman1980 for splitting the points with gfren.....

no problem
Points split between qfren and jman1980.

EE Moderator

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial