Your problem will be very difficult to solve based on the minimal amount of information you have given. I will make a few assumptions in order to help you find a solution. If any of these assumptions are incorrect, then your solution may be more accurately solved by addressing the issue related to my assumption.
Assumptions:
1) Not letting me on the internet means you cannot view a web page from the internet using your default browser or check e-mail using a mail client such as Outlook Express.
2) You are running a version of Microsoft Operating system.
3) Your computer is physically connected to the internet via an ethernet connection.
4) Other PCs on your network are able to get on the internet without "restriction".
Typical troubleshooting options:
1) If you are running a firewall, turn it off temporarily.
2) Try a different browser or e-mail application, i.e. Firefox if you normally use Internet Explorer or vice versa.
3) Use the Windows Command line to check your internet settings.
4) Disable your network adapter and re-enable it to see.
5) Reset your web browser to default settings.
Windows Command line tests:
1) Begin by issuing a Start - Run - CMD to access a Windows Command window.
2) Type "ipconfig /all" to check settings for each adapter present in your system.
3) Attempt to ping your firewall or router by entering "ping 192.168.0.1" or another ip address for your particular network.
Hopefully you can provide some additional details to help us determine the problem.