Hi found info of how to get your missing file back
1 Start your computer in Safe mode. To do this, restart your computer,press and hold down the CTRL key after your computer completes the Power On Self Test(POST) and then click safe mode on Startup menu.
2. Click Start and then CLICK run.
3. In the open box, type msconfig, then click OK.
4. In the System Configuration Utility dialog box, click Extract File.
5. In the Specify the system file you would like to restore box, type helpctr.exe and then click start.
6. In the Restore from box, click Browse, and then browse to the C:\Windows\options\install folder, where C: is the drive on which Windows is installed, and then click OK.
NOTE: Use C:\Windows\options\install if you installed a windows ME retail product. or C:\Windows\options\Cabs if your computer manufacturer installed Windows ME.
Windows ME installs the cabinet files by default, in the Windows\options\install folder. If these files are on your computer, you do not need your Windows ME CD-ROM because you can extract the Helpctr.exe from the appropriate folder on your hard drive.
7. In the Save Fill in box, click browse, and the browse to your C:\ DRIVE (where c:drive is the drive where windos is installed)and then click OK.
8.Click OK to extract the file.
9 Click Yes to the Destination folder C:\ does not exist. Do you want to create it? message.
10. Click OK to the The file has been successfully extracted message, and then click OK to close the SYSTEM configuration Utility dialog box.
11. Start Windows Explorer; Click START,point to programs, point to Accessories, then click Windows Explorer.
Locate the Helpctr.exe file that you extracted to your drive C.
12. Move the Helpctr.exe file to the C:\Windows\PCHealth\Helpctr\Binaries folder by right clicking the Helpctr.exe file and selecting Cut. Navigate to the Binaries folder, right-click the folder, and then click Paste on the shortcut menu..
13. Click Start AND THE CLICK rUN.
14. In the open box, type regedit, and then click OK WARNING: iF you use Registry editor incorrectly, you may cause serious problems that may require you to reinstall your operating system.
15. Locate the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\Helpctr.exe In the right pane, verify that the key is set to the following value:
C:\Windows\PcHealth\Helpctr\Binaries\Helpctr.exe
If this registry entry does not exist, create a new entry. To do this, follow these steps:
a. Locate the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths
b. Right-click App Paths, point to New, and then click Key.
c. Type Helpctr.exe
d. In the left pane, click Helpctr.exe.
e. In the right pane, right-click (Default), and then click Modify.
f. In the Value data box, type C:\Windows\PcHealth\Helpctr\Binaries\Helpctr.exe. and then click OK.
16 On the Registry menu, click Exit to quit the Registry editor.
Do that and you should find it has been reinstalled.
Keep us info how you get on.