Some of the related Symptoms of the problems are as under:
1. In Windows XP/Vista/7 based computer, Virus has disabled Task Manager, Registry Editor (regedit), Folder Option and not allowing execution of other system tools, for example: Process Explorer, Process Monitor, etc..
2. Unable to view hidden files.
3. Computer has become too slow.
4. There are frequent pop-up messages.
5. Anti-virus software either is not working or showing all .exe files corrupted.
The Easiest Solution
If you have got more than partition on your hard-disk and you know Windows Installation, then:
1. Take Backup: Move your important data from Windows partition (usually c:\ drive) to other partition/s.
2. Keep ready a recently downloaded Anti-Virus setup in CD/DVD or USB disk. Free or evaluation versions of Anti-Virus software such as AVG, Avast, Avira etc. are good. The only thing is that you should download a recent one, so that the Anti-Virus can have updated AV-definitions. (This step should be done on a virus free computer)
3. Insert Windows bootable CD/DVD and re-start the computer.
4. Install the Windows in the same partition (C:\ drive). Do select FORMAT option while installing the Windows. Leave other partition/s un-changed.
5. At first boot, before doing any activity, go to Start menu, click Run and browse the executable (.exe) file of the Anti-virus setup. Install the Anti-Virus and scan the whole computer.
Note: (a). Anti-virus software should be installed before doing any activity. ‘My computer’ also must not be clicked/opened before scanning whole computer through Anti-virus.
(b). You can also use command prompt instead of Run for installing Anti-Virus.
6. The Anti-Virus may detect several .exe files as infected files. You must either remove all these files or send to virus-vault.
7. You may need to restart the computer. Better to do a quick Anti-virus scan again.