install latest firmware on router
What computer make & model?
What computer OS? If XP, is it SP2 and fully updated?
Use a working Internet connection to download and install ALL the latest drivers from the PC maker's website. If you purchased the wireless adapter separately, download and install the wireless adapter drivers from the adapter maker's website.
Make a wired connection to a numbered port on the back of the router.
Can you log in to the routers admin page now?
* * * * *
Ultimately, you need to follow the procedure to install the latest firmware on the router:
The REFERENCE MANUAL is there, too.