You might want to copy and paste these instructions into a notepad file. Then you can have the file open in safe mode, so you can follow the instructions easier.
Boot into safe mode, under your normal user name(NOT THE ADMINISTRATOR ACCOUNT). See how
HERE.
In Windows Explorer, turn on "Show all files and folders, including hidden and system". See how
HERE.
Run HJT with no other programmes open(except notepad). Click the scan button. Have HJT fix the following, by placing a tick in the little box next to(
if there).
O2 - BHO: {f4be8bf6-d0ae-90f9-c304-701f3afae28d} - {d82eafa3-f107-403c-9f09-ea0d6fb8eb4f} - C:\WINDOWS\system32\oyogvi.dll
O9 - Extra button: Blog This - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra 'Tools' menuitem: &Blog This in Windows Live Writer - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O20 - AppInit_DLLs: oyogvi.dll
Click on the fix checked button.
Close HJT.
Locate and delete the following
bold files and/or folders(
if there).
C:\WINDOWS\system32\
oyogvi.dll
Reboot into normal mode and rehide your protected OS files.
Post a fresh HJT log and let us know if you're still having problems.