Can't log into Windows 7

Whenever I start up my computer, everything goes normally until it gets to log-in screen. There, it doesn't have the icon you click on to access your computer. Any advice would be appreciated.

While windows is booting press F8 and select Safe Mode. Boot into Safe Mode and check whether you are getting the login screen with user name icon for logging on. If you can login to the desktop, open Command Prompt with Admin privilages (rightclick on Command prompt command and select Run as administrator).

In the opened command prompt window, type
SFC /SCANNOW

This will start the system file checker and will rectify any corrupted system files. Once this is finished reboot and check.

If the system does not allow you to the desktop in Safe Mode, select Safe Mode with Command Prompt in the boot menu and use the above SFC /SCANNOW command.

I would also download, install and update Malwarebytes full scan in Safe Mode with Networking. If you can't get boot into that, download on another computer Microsoft Standalone System Sweeper write to flash stick or CD, boot to run a Full Scan.

Once the system is cleaned up, you'll likely need to repair System files as described, if necessary from System Recovery Options Command Line: SFC -SCANNOW Run in Command Prompt at Boot

I would also try Startup Repair several times and System Restore from the Recovery Options on F8 Repair My Computer menu, or DVD/Repair CD.