Computer having trouble connecting online.....

Yesterday I was on the computer and everything was
working fine, I was running IM and for some reason
Internet Explorer wouldn't open, and since I sort of need
more RAM, i thought that was the problem(which it might
have been) so I restarted my computer. It still wouldn't
work, so i shut my computer off and waited for a couple
of minutes then turned it back on again. Internet
Explorer worked now, but it was showing that refresh page
and a little box poped-up saying, in order to view this
page I must connect, so I said connect, but it didn't
work. Then i tried to log onto AIM and that didn't work
know either. I thought it might be because I got a trojan
2 days agao, but I scanned my computer and i had no
viruses, just some unwanted programs(like adware). It was
late, so I turned off the computer and went to bed. When
i turned it on today, a "Windows has just recovered from
a fatal error" message popped-up and I said Send error
report, I thought this solved the problem but it didn't
and my DSL still isn't working, I thought it might be the
router, but i put the DSL box straight into the computer,
not through the the router, and it still doesn't work. I
can get online through dial-up, but what good is that
when you have DSL or need a broadband connection? I have
no clue what could be the problem, so if you do or have
any clue what it might be, help would be appreciated.
Thanks in advance.