Adding Files To the windows system folder

[rancor0000]

I am using Windows XP which I installed (use to have 98) and after I ran anti spy and ad-ware programs I get a "cannot find file shell.dll" message when I try to install 16-bit software like old games and Borland C++, and other programs. The problem (I think) is that I do not have the shell.dll file in my c:\windows\system folder, it must have been deleted by one of the programs or something. Therefore, I downloaded it of the internet and put in the folder but a few seconds after I put it in it disappears, I try to uncheck the read-only attributes on the folder but it is reset as soon as I close the properties to the folder. I have done this using the Administrator account and have no security settings on the folder but still nothing.

Is there a way to unlock this so I can put the file inside it?
And if I am mistaken and putting the file in the folder wont fix my error then what will?

[Miz]

The "Read only" setting on folders is a meaningless setting that Windows ignores. Check any folder on your computer...they're all marked "Read only." Nobody but Microsoft programmers know why.

For the problem with running the DOS-based software, see if the information in the MS Knowledge Base article, Troubleshooting MS-DOS-based programs in Windows XP is any help.

[rancor0000]

No its not Ms-dos based programs , the problem is that if don’t have the shell.dll file in my system32 folder, now I have tried putting it in there with the repair console and it still deletes it.

Is there a way to re-install the system files from the "Windows Xp Install" cd that installs windows XP?

[Miz]

A 16 bit application is any software written for MS-DOS or early versions of Microsoft Windows which originally ran on the 16-bit Intel 8088 and Intel 80286 microprocessors. So generally, it is assumed that 16-bit software is DOS based.

You can run SFC (System File Checker) which scans the drive for altered and missing system files.

Go to Start>Run, type in "SFC /scannow" (without the quotes), click OK. It may ask for your Windows CD, so have it handy.

More details about running SFC are on this page.