I've lost the installation disk for my hp ...

If you do not have the disk you must download the software from Internet, follow instructions below,

Click here:HP Deskjet F2100 All-in-One Printer series - Download drivers and

A web page will open, follow instructions, select model, select operative system etc., and click on download .
Chose to download the file in my documents when asked.
After downloading, find the file,double click on the file ,then ifyou get in troubles, followthe instructions below to reset and reinstall drivers:

• Unplug printer USB.
• Go to control panel >> installed printers in Windows and remove (delete ) any installed printer from printer list.
• Download driver from website, or use the disk and run the install file.
  
• Follow driver installation wizard.
• Plug back printer when prompted from installation wizard.

Go ln line to HP and you can down load the drivers and you can order a new cd for HP