Windows 7: Windows 7 activation Help

Hi I purchased windows 7 earlier this year and installed it onto my laptop, recently the hard drive was damaged and I have just purchased a new hard drive for my laptop. Can i reinstall my windows 7 using the original disc and my serial key.
Thanks

Thanks, I originally used it on the old hard drive but this is damaged and cant be used. my new hard drive is clean and needs a operating system just didnt know if i have to buy windows 7 again

Is this Windows 7 which came preinstalled on the computer? You can reinstall it as often as you like to that machine for any reason and with any hardware change except the mobo.

No this was a seperate new windows 7 I purchased as an upgrade, just didn't want to try and install on my new hard drive incase it did something to it.
Thanks for the help, I know it's a silly question just wasn't sure

You'll need to leave the Product Key blank during install, then afterwards do the quick registry workaround given here to activate Windows 7 Upgrade version on a new HD: Clean Install with a Upgrade Windows 7 Version

With Upgrade version you can also migrate it to any hardware you choose as long as there is a qualifying XP/Vista OS which originally came on that machine, or you have a retail version of one of those qualifying OS's which are not being used during the period they serve as qualifier. The qualifying OS's do not need to be installed to clean install Upgrade version.

Sorry this wasn't an upgrade it is the full software, i have 2 discs 32bit and 64 bit and serial key, i think i used the 32 on my old hard drive. so will this still be activated on my old drive even though it is not working.

You can move full version wherever you want. anytime you want. as many times as you want for life - as long as it is on only one computer at a time.

thats great thanks for answering my question so quickly. don't know much about computers and thought i microsoft might block the activation and make me purchase it again. Big thankyou.