Trojan Downloader Istbar.4.H... problems

Close all programs.

Turn off System Restore

Run AVG Complete Scan

Turn on System Restore.

If you can't find Trojan horse Downloader.Istbar.4.G, AVG may have moved it to the Virus Vault. Check the Virus Vault

 

Can you try the safe mode to delete that file?

safe mode

 

Where does AVG say the file is:

Most antiviruses are notoriously bad about fixing adware files and ISTbar is a particularly difficult one to remove

the best way is to use a specific spyware/adware remover

Download and unzip or install these programs/applications if you haven't already got them. If you have them, then make sure they are updated and configured as described

Spybot - Search & Destroy from http://security.kolla.de
AdAware SE from http://www.lavasoft.de/support/download

Run Sybot S&D

After installing, first press Online, press search for updates, then tick the updates it finds, then press download updates. Beside the download button is a little down pointed arrow, select one of the servers listed. If it doesn't work or you get an error message then try a different server

Next, close all Internet Explorer and OE windows, press 'Check for Problems', and have SpyBot remove all it finds that is marked in RED.

then reboot &

Run ADAWARE

Before you scan with AdAware, check for updates of the reference file by using the "webupdate".
the current ref file should read at least SE1R4 16.08.2004 or a higher number/later date
Then ........
click the "Scan" button. and select full scan

When scan is finished, mark everything for removal and get rid of it. (Right-click the window and choose"select all" from the drop down menu) then press next and then say yes to the prompt, do you want to remove all these entries. You can safely ignore any MRU entries though and not delete them

reboot again