Avast detected that the trustedinstaller was a malware file and gave the option of deletion , i deleted it because i didnt know what it was, now my windows wont update i need that file , how can i get it , i have windows vista home premium 64-bit .
please help as soon as posible
Hi…
Check the virus chest in the main windows of avast and see if a copy of the file was sent there before it was deleted. If it’s there, you can restore the file but I would make sure that the detection was just a false positive and not for real. You can scan the file online, if it’s reasonably sized, here…
If a copy is not saved in the virus chest, you can try running “chkdsk /r” at the windows command prompt. Instructions (at the bottommost post) can be found here…
http://forums.whirlpool.net.au/forum-replies-archive.cfm/693150.html
Hope this helps! 
Best Regards…
If you send the file to Chest you’ll be able to restore it (it’s safer and wiser than direct deletion).
Maybe you can use System Restore to get your system back.
What avast version and VPS version do you have (right click the avast ‘a’ icon, select about avast) ?
The reason I ask is that this has cropped up recently in the forums, try a forum search for trustedinstaller.
Whilst none of that helps recover the file, you might check out this google search, http://www.google.co.uk/search?q=download+MS+trustedinstaller.