[nfbcs] Slow speed internet connection and error messages when downloading email

[Tonia]

Please help!  Any and all suggestions would be much appreciated.  I'm extremely frustrated and at a real loss for what to do right now.  Here's my problem.

I just got a new Del Inspiron desktop computer with Windows Vista Home Premium and MS Office 2007 Home and Student.  However, I had this same problem with the old computer (with Windows XP Pro and Office 2003 Pro). I have high speed BB internet service through Insight and I use Windows Mail for email (but I used Outlook before).  I've had the same issue with both computers.  It just sometimes seems to be much worse with the new one.  I realize some of that could be the learning curve for IE 7 and windows Mail; but I believe it's much bigger than that.  
My internet connection speed seems to be really slow (much more so with the new computer) and frequently drops offline.  For example, I tried downloading AVG a couple days ago but couldn't because the transfer rate was so slow and eventually timed out.  The transfer rate started out at what I guess is decent (250 kb) and then quickly dropped way down and fluctuated between 5 kb and around 40 kb.  I tried downloading the AVG 3 times with the same result.
I also have a similar issue with downloading email.  It generally takes numerous attempts and several minutes to finally get my new messages in my Inbox.  I continually get error messages before they finally download.  While the error numbers often change, they usually look like:

Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: 'mail.insightbb.com', Server: 'mail.insightbb.com', Protocol: POP3, Port: 110, Secure(SSL): No, Socket Error: 10053, Error Number: 0x800CCC0F

I've talked with 2 different levels of tech support with Insight and a tech came out to switch out my modem today, to see if that might fix the problem.  They all insist that everything looks good on their end, with the connection and modem; and that the problem has to reside with my computer.  Today, the tech concluded that it was a software issue; saying that I must have downloaded some kind of software that is causing interruptions in my internet connection.
Although, I don't have the solution, I tend to disagree with that conclusion.  As I said, this is a brand new computer that I've only had for a week; and the only software that I've added to it is Jaws.  Yesterday, I did download AVG on another computer and copy on to this one; but that didn't change anything.  Plus, I had the same issue with my old computer.  I never really dealt with the problem then though; because I assumed it might partly be due to the computer being a Gateway mini-tower and being a few years old.

Assuming Insight is right, in that it is a software issue, any ideas on what sort of software could be interfering?  Or any other ideas on what the problem might be or what I could do to resolve it?  For those of you who have Insight as your ISP, have you experienced similar issues?

Sorry for such a long description but I felt it necessary to adequately explain what is going on.

Very frustrated and eager for possible solutions,

Tonia