Big Problem! Help Please!

[Says_Who]

Hello everyone,

this is my first post here .. I just had a big problem with my desktop (I am using the laptop at the moment).

The problem is that Windows (my OS is XP) does not open any file (except: IE, My Computer, Recycle Bin) and all programs in the programs menu are missing! Even Windows Update link is no longer there

* I guess there is a problem with the file types and extensions (I created a new extension and called it exe and associated it with application, and some programs with their icons started to work, however i am not familiar with other file types, like dll).

The icons on the desktop and within folders are gone as well, and whenever I try to open a file, I get the following message "Windows cannot open this file".

I do not want to format my pc since I have a large number of files, and I don't think the problem is that complicated. Please if you could help me get the problem fixed, I would be grateful ..

Thanks in advance, and looking for answers

Note: I do not have any created restore point!

[Dotcoman]

What happens when you log on as either another user, or better yet the Administrator account or boot into safe mode?

[gonzo90017]

Did you try a system restore to the date before you did your changes? Start>Programs>Accesories>System Tools>System Restore

[Overclocked Doc]

Another possible option is to use the installation disk (assuming you have the full version) and do a "Full repair" of the operating system. This will leave all personal files intact, yet replace all XP files.
boot from cd > blue screen appears > (XP Setup) select enter > select F8 "agree" > select "repair"

Follow these instructions closely and do not choose "repair' on initial screen. It will appear that you are about to "install" XP again but you will be given the option to "repair".

One further note! You must have your "key" numbers on hand to do this.