what I suggest you to do is : PLEASE MAKE SURE YOU SCAN YOUR WHOLE HARD DRIVE WITH THE LATEST VIRUSES DEFINITION FILES. You can do this by taking off your hard drive and connect to another computer to scan OR please do not double click on any .exe files from other partitions after you reinstalled new windows.
So the problems is After you clean the viruses you won’t be able to log on to your windows desktop. I think here is the best ways to fix it:
Step 1: Create a BartPe Bootable CD
“ BartPE” (Bart Preinstalled Environment) is the bootable Windows CD-Rom or DVD from the original Windows XP that we can say Live CD that, very suitable for PC maintenance tasks.
To built it by ur selves please go to : http://www.nu2.nu/pebuilder/ to download the PeBuilder latest version and read the instruction to built your own bootable CD.
Step 2: Verifying and fixing the Userinit.ext
1. Insert the BartPE CD into the drive, and boot the system from the CD. Once the file loading phase is over, the Bart PE desktop will be visible.
2. Type Regedit.exe in the prompt, and press Enter. Select the HKEY_USERS hive
3. From the File menu, choose the Load Hive option. Browse to your Windows installation drive
4. Select the file named SOFTWARE (the file without any extensions), and click Open
5. Type a name for the hive that you’ve loaded now. (Example: MYHOUSE)
6. Now the SOFTWARE hive is loaded, and present under the HKEY_USERS base hive.
7. In order to fix the Userinit value in the loaded hive, navigate to the following location:
HKEY_USERS \ MYHOUSE\ Microsoft \ Windows NT \ CurrentVersion \ Winlogon
8. Double-click Userinit and set it’s value correctly. Example: Set it’s data as follows:
Note: If there is no Userinit.exe existed on your system, Please use the windows CD to copy it back as my previous post said.