I am using a computer that was given to me. A compaq. I can connect to the internet but when I click on most sites nothing happens. How do I start this computer working? I have windows.

I am using a computer that was given to me. A compaq.

General suggestions:

Ensure the networking configuration for the computer, any networking devices, and firewall is correct for your situation. The Networking Diagnostics - Helpful Hints (https://www.askmehelpdesk.com/networking/networking-diagnostics-helpful-hints-282387.html) sticky post in the AMHD networking forum has general diagnostic tips.
Uninstall and reinstall whatever browser you are using.

Gift computers tend to have issues, which is why they are gifts, and have often been "fixed at" by numerous people beforehand. Personally, I would obtain all the drivers and utility software available for the machine from Compaq's website (use friend's computer or local library), wipe the hard drive (Darik's Boot and Nuke (http://www.dban.org/)), and rebuild the Windows installation from scratch so I would know what I had. I would also first do a hard drive diagnostic with the drive manufacturer's diagnostic utility and run a memory tester (Memtest86+ (http://www.memtest.org/)) for a day to avoid having to do the rebuild work over again due to installation on failing hardware. Not having the original Windows installation CD or a recovery CD would limit your options to repairing instead of rebuilding.