I got a new laptop Sony VAIO E-series with win7.
I installed ubuntu12.04 x64 but I formatted Ubuntu partition due to some booting problems. From then I'm unable to boot with previous win7 and recovery disk for win7 is unable to load though it is available.
How can i regain my previous booting from win7?
It seems that you had installed grub boot loader on the ubuntu partition, you have erased afterwords.
If you plan to install Ubuntu again - just go ahead. During installation select to put grub to the root of your device, for example /dev/sda instead of /dev/sda2.
If not, you can still install grub to boot Windows and any other operating systems you may have using pretty much any Linux live media. To do this, follow the instructions, provided here How can I repair grub? (How to get Ubuntu back after installing Windows?)
Either way, grub should detect all the existing OSes and you'll be okay.
