Boot in Safe Mode, see how here.
Switch System restore OFF, see how here.
In Windows Explorer, turn on "show all files and folders, including hidden and system". See how here.
Next, open Windows Task Manager by pressing
CTRL+ALT+DELETE.
Click the
Processes tab, select the process (if there) and click
End Process for:
svcnt32.exe
html.exe <<== something like html...
Next, run a HJT scan and (if still there) place a tick-mark in the little square before:
...................................................................................................
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = res://shdocvn.dll/blank.html
O4 - HKLM\..\Run: [Start Page] C:\WINDOWS\system32\
svcnt32.exe home
O16 - DPF: {11010101-1001-1111-1000-110112345678} - mk

mSItSTORE:Mhtml:FiLE://
C:\html.mHT!http://205.177.122.27/docs/xxx/html.chm::/html.exe
<<== this could also be: html.exe or html.whatever, delete it
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) -
http://go.microsoft.com/fwlink/?linkid=39204
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) -
http://update.microsoft.com/microsoftupdate/v6/V5Controls/en/x86/client/wuweb_site.cab?1125150243031
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) -
http://update.microsoft.com/microsoftupdate/v6/V5Controls/en/x86/client/muweb_site.cab?1125150231734
...................................................................................................
Now click on the
Fix Checked button in HJT. Exit HJT.
When done, from between the above dotted lines, delete the highlighted
bold files.
Delete all files and directories from: C:\Documents and Settings\[username]\Local Settings\Temp
Repeat this for ALL [usernames].
Rightclick IE on the desktop, select Properties, click on
Delete Cookies, and
Delete Files.
Delete ALL files and directories from: C:\WINDOWS\Temp (except files dated from TODAY).
XP only: Delete ALL files from C:\WINDOWS\Prefetch.
Boot normal. When all OK, switch System Restore back on.