got infected user32.dll , how to repair ?

Got infected with a seriour virus or rootkit i don't know but the file user32.dll got infected and this is the most important file for windows 7,
i have scaned with avira and it can not delete or disinfect just report, i even scaned with malwarebytes and it does not find any infected file,

but avira keep saying it's infected but can not heal it,
anyone can help me what to do ?? i do not want to delete the file with AntiVirus i want to Disinfect/Repair the file because i googled about user32.dll and windows need this file to function correct,

thanks

 

Can you upload the file to VirusTotal and just tell us the number of scanners detect it as malicious like 2/43! https://www.virustotal.com/ I recommend that you read this also: https://www.wilderssecurity.com/showpost.php?p=1533481&postcount=3

TH

 

ask for assistance from one of the volunteer malware removal sites
https://www.wilderssecurity.com/showpost.php?p=1533481&postcount=3

 

I would scan and clean with one or more of the many Antivirus Rescue CD's such as:

1. Kaspersky Rescue Disk 10
2. Dr.Web LiveCD
3. BitDefender Rescue CD
4. Avira Rescue System CD