First of all, what error does Firefox give you when it can't load Google? That's likely to give some indication as to the problem.
If you save the file to the local disk and open it from there, is it still slow?
Do you have slowdown issues with other networked applications; is is slow to send an email for example?
One common problem causing slowdowns in network access is a badly configured DNS (Domain-Name System), which is used to convert hostnames like www.google.com
into numbers called IP addresses, which are used to connect to the server.
Open a terminal and type in this (You will need the bind-utils package installed for this to work).:
This should return almost immediately, with about a page of technical information about Google's domain name setup. If it takes a second or longer, then it's likely that your DNS setup is wrong.
The next thing to try is a traceroute, which will time each network "hop" — the time taken to send a package between different machines between you and your server. To try this with Google:
This may take a few seconds to run and lists times for each individual hop; each one should be under about 100ms and there shouldn't be any of 1s or longer.
That won't solve your problem by itself, but should help us to get more information to help to diagnose your problem.
— Robert J Lee