Router problems

[#1]

I had a perfectly good, working set-up.
In my study I have 2 PC’s (1 Vista, 1 XP pro) and an Oki laser printer, upstairs in the den the kids have a PC running XP pro. They were all connected to Netgear router in my study.
Number one daughter decides to buy Vista laptop (to use in her bedroom for now, off to Uni next year), number two daughter still using PC in den. Hubby also decides to get a laptop for his music, photos and crafting.
Problem: Router doesn’t have enough ports to accommodate 2 new laptops.
Solution: Buy wireless router. SMC Barricade 7904WBRA-N. Connect 2 laptops wirelessly.
Problem: Both daughters complain about speed (slow).
    Number one daughter complains about dropped connection and speed when she uses laptop in her bedroom, no more than 20 feet away from router, although if she brings it downstairs it is usually ok.
    Every time any of the computers are shut down the internet disconnects, then when you next boot up you have to log into the router and re-connect to the internet.
Solution: That’s where you come in!!! Help please, It’s all driving me mad!!!

[#2]

Sorry I don't know that router but the disconnection of internet and need to manually log in to the router is not normal.
Sometimes you can get a conflict between Vista's built-in WiFi utility (Zero Config) and any installed adapter software, it's normally best to use one or the other rather than both.  I prefer to only install the driver for the wireless adaptor and let Vista handle the rest, once you have set up a wireless 'profile' it should automatically connect (you would normally set your home network as the preferred connection (always connect if available or something to that effect).
I have 4 pcs in the house, all on wireless and all connect without trouble, though I did have to change the adaptor on one desktop (farthest from the router - around 20 feet as the crow flies - can they fly through walls?) to get a reliable connection, never worked out the reason.
If you are able, it might be worth (even temporarily) moving the router as far as possible to minimise the distance to se if performance improves on the wireless.
My internal walls are thin (modern house), some structures are less friendly to WiFi.
The disconnects when any PC shuts down sounds like a real problem, it *could* just be a set-up issue with the router or it may be a fault, hopefully someone with knowledge of your model can assist here.
If you don't mind running cables you could buy an ethernet switch to add ports to your old router but that does remove some of the 'freedom' you expect from the laptops.  Sometimes using an adaptor from the same manufacturer will give more reliable wifi connection, especially for certain 'N' wireless set-ups.

[#3]

Thanks walker23, it is a bit of an obscure one I must admit. SMC do telecommunication products, I seem to remember having a phone system by them somewhere I once worked.
Never thought about conflict, I did all the set-up from the XP PC as the old Netgear had been set-up from the XP one before I purchased the Vista PC. Do you think I should uninstall it and start again from the Vista PC?
I do have an adapter that came with the router, its sitting in the box at the moment, I was going to use it when I move the PC out of the den into number 2 daughters bedroom to save re-routing cables but I could try it in number one daughters laptop and see what happens.
Walls are not too bad in the house (30's semi) but I dont think I can get router any nearer to her bedroom.
I dont mind running cables but the other reason for the new router was to upgrade to adsl2 in a vain hope of increasing speed - I'm on an upto 8meg connection but never get much more than 1meg. I'm about 2 miles from exchange as the crow flies.

[#4]

Quote

Every time any of the computers are shut down the internet disconnects, then when you next boot up you have to log into the router and re-connect to the internet. Solution: That’s where you come in!!! Help please, It’s all driving me mad!!!

with it being all PC's one would assume that the settings that need tweaking are going to be the router ones
firstt time ive seen shuch a fault and that router model
can you confirm if you have the latest firmware running, also have you tried a hard reset  
http://www.smc.com/index.cfm?event=downloads.searchCriteria&localeCode=EN_GBR

[#5]

As the SMC is not exactly ome of the most popular routers it is relatively difficult to offer much advice.
Is there any possibilty of borrowing a spare wireless router from anyone (friend, neighbour, work colleague) just to rule out any router faults?
I use a 'g' wireless router that was bough on a special offer from a large supermarket, so far the wireless side has been excellent (I did have problems with ADSL disconnecting a few days ago but found that my 'better half' had put a pack of christmas cards on top of the router and it had got very hot, it reconnected as normal after it cooled down!).  I think your model is 'n' wireless which might be a little more 'fussy' than the more standard 'g' type ('n' wireless is really an enhancement of 'g' wireless but has been in 'draft' standard for a long time so it is potentially more prone to incompatibility.
ASBO DOG is definitely correct that the router settings are most likely to be the ones to check based on the information he refers to.
Does your PlusNet contract include 'free' hardware, you might be able to request a wireless router for the price of shipping if your contract allows.

[#6]

Quote from: ASBO

Quote Every time any of the computers are shut down the internet disconnects, then when you next boot up you have to log into the router and re-connect to the internet. Solution: That’s where you come in!!! Help please, It’s all driving me mad!!! with it being all PC's one would assume that the settings that need tweaking are going to be the router ones firstt time ive seen shuch a fault and that router model can you confirm if you have the latest firmware running, also have you tried a hard reset   http://www.smc.com/index.cfm?event=downloads.searchCriteria&localeCode=EN_GBR

I probably dont have the latest firmware as I haven't updated it since I got it. Have done a hard reset though.