Decimated broadband speed...

[#1]

Hi
I've had plusnet broadband for 2 -3 weeks and everything was running fine until about 3 days ago.  All of a sudden pages took an age to load and youtube, i player etc became unwatchable due to instant and constant buffering.
I've tried everything I can think of including disc cleans, moving the lap top to within about 2 feet of the router, hooking up through the ethernet cable, disconnecting the phone and only leaving the broadband cable in, deleting unnecessary programs from my laptop and running scans, but it doesn't improve and all the scans etc tell me my laptop is fine.
I've ran a few speedtests on it and they're coming back at an atrocious 0.1mb download and 0.06mb upload speed.
I'm fairly new at all this, so any help would be appreciated, but surely I shouldn't be getting problems this bad this early..
If it's any additional use, I'm running Windows 7 and my laptop is brand spanking new...
Ta
Edit to say, previously, when I hadn't been using the internet (which is fairly often) I had been switching my router off.  I've since read a few things which suggest the router should stay on, but like I say, I'm a total novice and no one from Plusnet advised me the router should stay on, nor did it mention it in the setup instructions.... 

[#2]

Hi,
Yes, you should leave your router switched on all the time. When you switch it off and back on, it will take some time for the connection to stabilise.
Each time you switch off and back on, your router and the exchange will have to go through the merry dance of negotiating the best speed and stable connection. You may find that it could take up to 72 hours before you see a stable connection.
Switching off the router could make the exchange hardware think that there is a fault with the connection and it will back off the speed until it gets a reliable link.
Leave it on for a few days and then see what kind of speed you are seeing.
Hope everything works out for you. I've got a connection but it varies between 2.5mB and 704kb randomly!

[#3]

Thanks very much for the response...
Like I say, I'm a total novice at all this and had no idea about the router situation..
Another stupid question possibly, but when you say leave the router on, you mean literally leave it on?  There's no standby button or anything like that?
Thanks!

[#4]

Yep...once it's up and running there's no need to touch it again. Just leave it powered up and connected to the internet.
There is no standby on a router.

[#5]

Thanks very much for all the info, that's really useful.
Bit strange that it didn't mention it in the setup, you'd think that would be a fairly important piece of information for novices like me!!
Further edit to say, now the router has been on constantly since 7 30 last night, should I still be getting the following speeds?: