I'm searching for a pdf creator for Windows with the following features:

- do not require admin privileges to install or use
- free (freware, opensource etc.)
- creates a pdf printer or do something similar to print web pages, documents, worksheets etc. easily, without the need to change something in particular softwares (i.e., I would not like to install MS Office, OpenOffice, Firefox, Thunderbird... add-ons)

I would like to use it as common user in computers that does not have pdf printers.

You can try this function is very powerful PDF software, there are those functions that you say, you can learn from it and see that you have no help.
More useful Software please visit the Web site:
http://www.oxpdf.com/pdf-creator.html

thanks, but it is not freeware

It installs as a printer (driver), so I'm not sure if you need admin-privileges for install.
You have access via the print-function of your applications.
It's not opensource but free

http://www.pdfforge.org/

Does this pdf creator can create a pdf printer or do something similar to print web pages. I am searching for a solution for so long.