Hit
Ctrl+Alt+Del and from the menu click >>
File >>
Run. Type
explorer and hit enter
If doesn't help, under shutdown >> restart. And see if it works.
If it doesn't, Download a copy of HijackThis and save it to your desktop in a folder. Do a scan and save the HijackThis logfile. Do not remove anything. Post your log file in the
Malware Removal Support & HijackThis logs forum. Link to HijackThis:
http://www.trendsecure.com/portal/en-US/threat_analytics/HJTInstall.exe