I tryed what u told but still i am not getting.
and one more thing is
my project is saved in the following path.
"C:\Users\Administrator\Documents\Visual Studio 2010\Projects\WebpartUploadFiles\WebpartUploadFiles\"
And my assembly path is :C:\Windows\assembly".
I am really sorry to say this,I am not getting which you send
1. Copy mydll.dll to temp
2. Open Windows Startmenue, type "powershell" open the Windows Powershell or the SharePoint 2010 Administration Shell
3. Set alias to Gacutil, type:
Set-Alias Name:Gacutil -Value "C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\gacutil.exe"
4. Add dll to gac, type:
Gacutil /i C:\temp\mydll.dll".