I've had my router connected to the computer downstairs for about 2 years, it came with a USB adapter for wireless upstairs.
It all worked fine until the adapter fell off my desk and snapped.

So i purchased a new one, installed whatever it said everything was fine.
Then it started to drop the connection usually between 5-20 minute intervals. I think i've had go 2 hours without it dropping the connection.

In my router settings, i've tried altering the MAC adress to fit the one on my usb adapter but that will not allow me to access the internet at all.

Where as if i have it set as the MAC adress on my old adapter, the net works fine but it keeps dropping the connection..

It's a pain when watching videos on the internet because it usually drops when watching the videos.

I read that because there isn't activity going through the wireless it resets or something like that.

Any help would be appreciated, as it's starting to get annoying.

I will try my best to provide any information i can to help.

how far from the router is this wireless connection?
does the drop connection only happens when you are watching video, or all internet activity.
can you change the channel the rout is one
have you tried restting the rout sing getting the new wireless adapter?

I don't have £25 to spare on another wireless adapter.
It seems to be only when watching videos, and then for a while after that and it settles down.
The router i dont know im upstairs and it's down, it isn't that far.

OK, it is most definately linked to videos. I cannot watch a youtube vida for more than 10 seconds without my connection dropping, and it carries on dropping regularly for 10 minutes after that. Then it's fine until there's a video on a page trying to load.