If i understand right you mean your COA sticker on your machine is unreadable, if so then you can retrieve your product key out of your system
Your key is stored in the registry but is encrypted so you will need a software solution to extract it for you
Something like this Windows 7 Key Finder - CNET Download.com
Please post an MGADiag report - the chances are that the Key reported by any KeyFinder application (such as Speccy/Belarc/MagicalJellyBean/etc) is going to be the OEM_SLP Key which is to all intents and purposes, useless to you.
The MGADiag will at least tell us which Key is in use, and will allow us to troubleshoot any current non-genuine message you are getting.
Please follow this tutorial and post an MGADiag report - then we can see what the problem is.
Please also state the Version and Edition of Windows quoted on your COA sticker (if you have one) on the case of your machine (or inside the battery compartment), but do NOT quote the Key on the sticker! http://www.microsoft.com/en-us/howtotell/Hardware.aspx
Ignore errors produced when clicking on the Copy button - they simply mean that the tool could not create the backup files for some reason. The data is still copied to the clipboard for pasting to your response.
My Computer
At a glance
Win 7 x64 Home Premium (and x86 VirtualBox VM...i3 370M/i7 6500U8GB - finally :)/8GBit's an i3, dude!/dual Intel&nVidia
Computer type
Laptop
Computer Manufacturer/Model Number
Asus K52F or Lenovo B51-80
OS
Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
CPU
i3 370M/i7 6500U
Motherboard
Asus/Lenovo
Memory
8GB - finally :)/8GB
Graphics Card(s)
it's an i3, dude!/dual Intel&nVidia
Sound Card
onboard
Monitor(s) Displays
15.6" built-in
Screen Resolution
1366x768/1920x1080
Hard Drives
750GB Seagate internal
Sundry external drives attached to other computers on the local network
1TB SSD on the Lenovo
PSU
n/a
Internet Speed
as much as I can get - usually on a dongle/phone, so <1MB/s