Activation help needed

Hello everyone
My first post and I feel a bit stupid for asking for help straight away.
There doesn't seem to be a forum for newbies to pop into and say hi, so I hope no one minds.

My PC came with an oem version of Windows 7 home premium 4 months ago, (bought from a reputable internet vendor) but I never got to use it for more a few days because I was taken into hospital.
I get home a few days ago, turn the PC on and am greeted with an expired activation warning. I tried re entering the activation code several times but the same message came back 'this code cannot be used on this computer, please retype, buy another key...etc'

I noticed your forum mentions in several threads that activation problems can be sorted via an automated phone call to Microsoft but this is no good for me as I am deaf, on my own with no one to assist me with this.

I was thinking maybe my best bet would be to follow the MS link and buy another activation key code? Is this emailed to me? Would it 110% work - I don't want to waste more money and end up hving the same activation probelms.

Thank you so much for helping, really appreciate it

Marmaduck (God, what possessed me to choose that username!)

Hi OS :)
Thanks for the welcome.
I will try those two options you mentioned. I'm not really worried about losing any data as the computer was only used for a few days.
Thank you :)

Read about rearming activation here, same for Win7: Vista: Activation and the SLMGR Command (options explained) | Microsoft Vista | Tech-Recipes

Hi Guys :)
Bit of an update. A friend came by on the off chance and I asked if he could help. He phoned the activation helpline for me, typed in lots of numbers into the phone and was given sets back (by an answer machine). He said he was short of one set? (typed in 9 blocks of 6 numbers but only got 8 sets back).
I ran upstairs with the numbers to power up the PC, tried to find the 'activate your code' pop ups, accidentaly hit enter without typing anything in....and got a activation successfull popup. I haven't done anything yet? Is there something else wrong with my PC?

Hi Phone man, Tews :)
The description in the 'system' tab says 'windows is activated'
Not sure how it sorted itself out becaused I never used the code given by the automated phonecall.
Can't really explain what happened, maybe bacause I changed the time from US to UK hours? All is well now anyway & I'm sat here as a windows 7 newbie really, (from XP) the only experience I've had of W7 was a couple of days about 4 months ago, looking forward to getting stuck into it.

Cheers
Marmaduck

Hi Tews. Will definitely back up my system to a seperate partition. I've got something called Acronis True Image 2010 which I think will do just that.