help how to solve usernit logon application error

save your eventlog and post it here: http://technet.microsoft.com/en-us/library/cc775447(WS.10).aspx

Most UserInit problems are a result of virii/spyware....

 would actually do a few things first........Install and update Super Anti Spyware and reboot to Safe Mode. Then do a full scan, and see what it finds. Or, if you prefer, scan with MalwareBytes....

SUPERAntiSpyware.com - AntiAdware, AntiSpyware, AntiMalware!
http://www.superantispyware.com/
One of the best on the market (and it is free, although you can upgrade and get Real Time Protection). Under the Options, go to Scanning Control> and make sure it is set to the following.....

Terminate memory threats - checked
Ignore non executable files - unchecked
Scan only known file types - unchecked

Manual Definitions Download....
http://www.superantispyware.com/definitions.

MalwareBytes
http://www.malwarebytes.org/

Can also use Combofix. (stolen from rpggamergirl's postings...)  :)

Here's the instructions, if it doesn't run at first, then redownload and rename before saving to your desktop.
Please download ComboFix by sUBs:
http://download.bleepingcomputer.com/sUBs/ComboFix.exe 

You must download it to and run it from your Desktop
Now STOP all your monitoring programs (Antivirus/Antispyware, Guards and Shields) as they could easily interfere with ComboFix.
Double click combofix.exe & follow the prompts.
When finished, it will produce a log. Please save that log and attach it in your next reply by pasting it in the "Code Snippet" or "Attach File" window.
Re-enable all the programs that were disabled during the running of ComboFix..

Note:
Do not mouse-click combofix's window while it is running. That may cause it to stall.
CF disconnects your machine from the internet. The connection is automatically restored before CF completes its run. If CF runs into difficulty and terminates prematurely, the connection can be manually restored by restarting your machine.

If needed, here's the Combofix tutorial which includes the installation of the Recovery Console:
http://www.bleepingcomputer.com/combofix/how-to-use-combofix

Personally, I wouldnt install the recvovery console.

Or, we can start with a Hijack This Log file....

HijackThis!
http://hijackthis.de

Also, check in c:\Windows\system32, for the userinit.exe file. How big is it, and whats the date modified on it?

Also, also.....

Paste these 2 lines into a Start>Run>Cmd DOS Box, and give paste the results.....

reg query "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" /v userinit
reg query "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" /v shell

try also with online scans:
http://www.pandasecurity.com/activescan
www.bitdefender.com/scanner/online/free.html 
http://www.f-secure.com/en_EMEA/security/security-lab/tools-and-services/online-scanner/
http://security.symantec.com/sscv6/home.asp?langid=ie&venid=sym&close_parent=true
http://housecall.trendmicro.com/
http://www.kaspersky.com/virusscanner
http://home.mcafee.com/Downloads/FreeScan.aspx?ctst=1
http://www.eset.com/onlinescan/
http://onecare.live.com/site/en-us/default.htm

Make sure that you have the latest Service Pack install on your System. Latest being SP3

Combofix and hijack this are good but not a solutions for all.

Try using a spyware program like
Spyware Doctor  http://www.pctools.com/
or
my favorite Spysweeper www.webroot.com

hello, i tried everything that you said , no success, my pc is getting worse, the programs are failing, the internet sometimes is not open any more, the folders doesnt open when i make click or right click, i have to restart each 5 minutes to work more or less properly, every program now has a problem im working in a program and i try text and closed and i loose everything i was doing, please help in this what can i do,  i dont have the cd of the xp i dont know how to install it again if this is the only solution. i hope you can help me. anyway i attach the errors that john ask with that programs just in case, is a way to solved. thanks before hand
USERNIT.txt

ah i forgot, now is not just usernit, is something about dll, sometines mv, and an error idlist,:02036 that is not found when i start the pc, all this windows appear and its no way to close them just the idlist error is posible the another ones remain there.
if somebody has a solution any please let me know .
del.

"usernit file = 43.5k"
Thats about double the size of a standard Userinit.exe file......
I would seriously look at replacing it from the install CD, or from another working PC. Delete the copy in c:\windows\system32\dllcache first.....

"Find String (QGREP) Utility has encountered a problem and needs to close.  We are sorry for the inconvenience.
EventType : BEX     P1 : findstr.exe     P2 : 5.1.2600.2180     P3 : 41107c09
P4 : unknown     P5 : 0.0.0.0     P6 : 00000000     P7 : 008a023d    
P8 : c0000005     P9 : 00000008   "
When does this occur? as a result of the reg query commands?
 

Just go to start>run>regedit, and go to the following key in the registry, and give us the values for Shell, Userinit and Winlogon. Right click the whole Winlogon key, and select Export, and save here if needed....

im sending what jhon ask me for, the winlogon, today says windows logon ui has encontered a problem, and the userinit as well, this is a nightmare, does in windows vista usernit works to replace it with the one on this pc?

Did you try running Combofix yet as John had suggested?

Combofix will replace any patched userinit.exe if a clean one is found in the system.
The log will also show us if other system files have been patched... could be a file infector at work there.

No, dont use the one from the Vista box, as it is a higher version....

hello nothing that i did worked , so i reinstall xp and im installing the programs 1by1 i dont have the error anymore but was no way to fix it , i had to reinstall xp because somebody suggested to install SP3, and from there the pc didnt start any more, i checked what happened and before you install sp3 you have check your system of course i didnt and my pc just was off and sometimes with an blue screen error.so i was tired already of all of this , i think the more wise solution when this happen in the system before everything is worse is to do a clean install of xp, then drivers, etc.
anyway thanks for trying to help me.
regards.  

thanks jonh to be there everyday with solutions for my problem, i appreciate a lot your help.