The IDE per se does not require admin permissions.
You probably did not have to do that on your previous company PC, right ?
I took a backup of entire Hard disk of my old pc to new one and now I am trying to open those old .X projects in IDE installed on new PC.
This does not tell how you really "copied" all the data. (assuming Windows)
My first guess would be that you copied all the file attributes including ACLs, permissions etc, for your "old user".
You could fix that on the new location, but a) this requires good knowledge, and b) if you don't have the rights (company admins) to do so, you can't
To work that out get one full project from your old PC, copy it to a thumbdrive (USB stick) which is not
formatted as NTFS, but e.g. FAT32. Then copy it to your new PC. This should implicitly remove the ACL stuff and you can try whether you can open this project as normal user.