Really not enough information.
No error messages, pop-up windows? What OS are you using? Once connected is Internet performance normal?
If your PC boots up and "takes a while" the delay could be any number of things. Not necessarily an internet connection issue.
Start by downloading and reinstalling the network adapter drivers via the manufacturer's website.
If reinstalling the drivers does not improve connection time, open Task Manager to observe what your computer is doing: may be some update trying to complete, some backup launching, an AV scan of some sort. Slowing everything down.