In such case, you may not be able to get into safe mode with networking now.
It is more safer to get into safe mode with command prompt：
- As the computer is booting but before Windows launches, keep tapping "F8 key" continuously > "Windows Advanced Options Menu" comes up > highlight "Safe Mode with Networking" option > press Enter key.
- You will see a little black window with a flashing slash after system 32\, then type 'explorer', hit enter key
- When in, ignore prompt box, if any, go straight to control panel to create a new user account with administrator right
- restart your computer and get into that newly created user account
- go into Drive C and find folders entitled the name of the locked up user account
- navigate to Roaming and Temp folders to find files with abnormal names (cus names can be different) and delete them.
- restart back to original locked up user account (normal mode)
method 2: If you still see the lock up page: restart the infected computer (cold restart)> keep tapping F8 key > select safe mode with command prompt again > see a flashing slash > type 'net user /add' > hit Enter key > restart the computer and get into that newly created user account named 'net user' > Go into Drive C and find folders entitled the name of the locked up user account > navigate to Roaming and Temp folders to find abnormal files and delete them > restart back to original locked up user account (normal mode).
method 3: if the two above will not show you a usable desktop, you may need to go to places like center for computer virus removal. They will make you a mini system to help enter into the system first so as to delete the virus.
Hope the above info can help you out.