Just dragged myself into 21st century and got BB. Very pleased, except for one annoying thing - if I spend some time just doing non-internet work (letters, photos, etc) and then return to try and surf, it seems to stop and pages will not load and my email will not check.
By trial and error (and some frustration!) I found that if I close down and restart, everything works as normal again. But it's so annoying having to keep doing restarts.
If you are using a Router you could reset your router rather than closing down and re-starting. To reset the router simply disconnect/switch off the Power to the router, then wait at least ten seconds and then re-connect/switch on the router.