I can't see Hidden files/folders in my computer. Even I enable the option "Show hidden files/folders" in "Tools -> Folder Options", its automatically disabled again.

Solution1: Go to your Start menu, click on Run and open up your Registry Editor by typing "regedit" without the quotes and pressing OK.

Once there go to: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folde r\Hidden\SHOWALL

Delete the value CheckedValue. (Its type should be REG_SZ and data should be 0 or 1.)

Create a new DWORD value called CheckedValue (same as above, except that the type is REG_DWORD) by right clicking on the right pane->New->DWORD Value. Modify the value data to 1 (0x00000001).
Solution 2: Open regedit and goto:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
In right-side pane, change value of "Hidden" to as following:

1 - To show hidden file
2 - To not show hidden files

If it doesn't work, then scan your computer with an anti-virus software.


2. Task Manager Disabled:

Using Group Policy Editor - for Windows XP Professional to Enable Task Manager.

* Click Start, Run, type gpedit.msc and click OK.
* Navigate to this branch:

User Configuration / Administrative Templates / System / Ctrl+Alt+Delete Options / Remove Task Manager

* Double-click the Remove Task Manager option.
* Set the policy to Not Configured.

Enable RegEdit [It is not tested]

REGEDIT4
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersio
n\Policies\System]
"DisableRegistryTools"=dword:00000000

Save the text file as any name u with extension .reg
example:- "enable.reg"
After that double click to run the file.

Note:DO SCAN YOUR MACHINE WITH A GOOD ANTIVIRUS. BECAUSE THIS PROGRAMS DON'T TURNED OFF BY HIMSELF OR AUTOMATICALLY. IT HAS TO A VIRUS EFFECT OR A ADMINISTRATOR HAS TO MANUALLY DISABLE THIS PROGRAMS.