Didn't get a chance to respond earlier - I was visiting some of my family members for the first time in months (I was away at university before).
@ Iceman - Your advice sounds familiar - I got help before from a tech site, and it seems that it was something to so with the router not adjusting to the IP address. But I'm not really into networking, and I don't remember the details, or what I did to fix it.
But this is the right track now.
I am pretty sure there was a setting under my network settings which needed to be changed, but I don't remember what it was.
I tried pinging Yahoo - no problems with either the router or modem (except when my connection ceased, of course). Here is a typical line:
Reply from 209.73.186.238: bytes=32 time=53ms TTL=50
The last two variables were different most of the time.
As for my modem, is a Speed Touch Home, but I don't know the specific model number. All of the tech teams I used to speak to seemed to be satisfied with just that (although they could never figure out the problem). Also, I cannot stay connected for hours - about 15-20 minutes is the maximum. The crashes occur at any time - while updating software, when my brother runs Bitorrent, or when either one of us is just browsing online.
Thank You very much so far.