Vista - Problem with WSOCK32.dll

Hello, im totally new to this so please stick with me.
I keep getting this message appearing when I try to install new software:

C:\Windows\system32\WSOCK32.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support.

On the top left of the message box it names the file I have tried to open and it states Bad Image.

Looking on the web I have noted that the wsock32.dll file might need replaced, I have downloaded a copy and tried to replace the old one in the System32 folder, but Vista will not let me do this. I cannot reinstall vista as I was not given a disc when i purchased my computer.

Thanks for taking the time to read this and any help would be really great.

legweek

there is one thing you can try. try running a system file check. it verifies and fixes system files. go to search type>cmd>right click and run as admin)>type sfc /scannow. the reason vista wont allow you to swap files is that its in use. You might be able to if you boot into safe mode (F8)

Hope this helps

Ken