In your situation, you may not be able to do much even if you boot up in safe mode.
There are a few options.
1) reformat and reinstall your Windows ( leave it as last resort )
2) take out your hard disk and install as secondary drive in another PC that have a good anti-virus program. Boot up on that PC and scan your infected hard disk.
3) You install CLAMWIN
ClamWin is a Free Antivirus for Microsoft Windows
that uses the GNU General Public License by the Free Software
Foundation and is free (as in freedom) software.
There is a portable version of ClamWin where it can be install into an USB pendrive as small as 64 MB.
First use another PC to download Clamwin portable anti-virus
and install Clamwin portable on a USB thumb drive.
http://portableapps.com/apps/utilities/clamwin_portable
Update the latest anti-virus definition files.
Set the preferences to delete or move virus to a quarantine folder.
How to configure ClamWin
http://support.real-time.com/open-source/clamwin/index.html
When the USB pendrive is ready.
Boot up the infected PC in safe mode.
If possible, disable system restore on the infected PC.
Use the USB drive with Clamwin Anti-virus installed to scan the infected PC.
Scan all hard drives for viruses.