Just got disconnected again while typing this reply to you 
Back Again!
The work around below was posted over at the TT forum a while ago, it might be worth a try, all credit to Ken.
Since I provided my original suggestion to regain Broadband connection for your PC a number of things have happened.
Firstly, to those who say TalkTalk MUST resolve it's problems, I FULLY agree and, when it is resolved, we should all seek recompense for all the expenses we have incurred, whether our personal time or money spent on not needed equipment. If necessary, if a lawyer reads this, maybe a group action would be the way forward.
To those who just, out of hand, say they will NOT try what I have suggested, then so be it, if you want to go on having problems, when what I have suggested might at least enable you to regain some sanity and a stable connection that enables you to again enjoy the internet and doing those things you would prefer to be doing. As I have said to some people if, when driving you encounter roadworks and a diversion is signposted, would you just sit in your car at the roadworks and wait until the roadworks are completed or would you take the diiversion until the roadworks are completed. I wouild believe you would do that later so why not give my suggested work around (diversion) a go??
I have now been, except when I have checked what the situation is without using my work around and still found the disconnections happen about every 5 or 6 minutes, been solidly connected for 9 days including, without restarting my PC so it's working memory did not get too fragmented, had 1 session where I was connected for 3 days and my current connection has now been in place for over 74 hours.
For anyone reading this for the first time, or again and wants a reminder, this is what you need to do to try out my suggested work around:
"1. Broadband Connection
Select "Properties, then select "Options", where it says "Idle time before hanging up" set it to NEVER, if that is not the current setting. It could also, so as to speed up any needed reconnection, be best to set "Time between redial attempts" to 1 second and to tick "Redial if line is dropped".
2. E-Mail Facility (Windows Live Mail and Outlook Express and similar in other E-Mail facilities)
When running select "Tools", select "Options", select "General" and then set "Check for new messages every" so it is 2 minutes, click APPLY, then click OKAY and then restart the E-Mail facility.
3. Starting of Broadband and E-Mailk Facility
The E-Mail facility needs to be up and connected to Broadband inside of 4 to 5 minutes, else a disconnection is highly likely to occur."
As I keep saying just because this may give you a steady connection keep checking if you are still getting, if you do not do what I have suggested, the regular disconnections AND, if you do, bombard Talktalk with that fact until you find your connection has been stabilised by THEM.