I accidentally deleted the linux partition from windows. When I restarted the system, a black screen comes with "grub rescue" written on it.
How should i get out from this problem ?
I am very new to linux, so please be as descriptive as possible...
Please help...
Thanks in advance..

What version of windows are you running?
You'll need to download either Rescue console for wins xp or for wins 7 you'll have to go to digital river downloads to download the dvd.iso for your system to fix mbr.
Here there are disks for all 3 winsxp 7 & 8.
https://neosmart.net/wiki/

Generally Microsoft Windows does not recognize Linux partitions, unless you formatted it to NTSF.

NTFS is not a Linux partition, although it is read/write-able in Linux. So's FAT and it's variants. Linux partitions (actually partition types are something different - what you are implying here are file systems) are generally those that support hard/soft links, device nodes and the like. There are plenty of those, and widespread are ext2/3/4, reiserfs, xfs...

OP You can just simply install grub on the MBR, and put an entry in grub.cfg that points to the windows bootloader on the boot partition like so:
You can even type the above commands directly at the grub prompt and make your system boot.

well a linux OS is no longer installed then
you need to reinstall the Microsoft bootloader

however the MS windows 7 install dvd dose not recognize a NON microsoft formatted partition

you will need the live cd "Gparted livd cd"
http://gparted.sourceforge.net/
reformat the boot MBR to ntfs

then use the win7 install dvd ( you DO have one ? right ? ) to fix the MBR

Start your windows OS; invoke cmd prompt; go to windows\system32; run bcdedit.exe. Delete every mentioning of the other OS.

What if I want to delete windows too and install some other linux OS?
What should i do in that case?

Any distro that you install can remove windows or linux during installation. Just select Use whole drive option.