You can access Recycle Bin through MS-DOS also! The recycled files are stored in directory called "RECYCLER" in Window XP and "$Recycle.Bin" in Windows 7.
Step 1: To get into MS-DOS while booting, press F8. You'll see an option called "Safe Mode with Command Prompt". Select it and press enter.
Step 2: You'll be asked to select the Operating system to start. Select your OS and press enter.
Step 3: Next, you'll see the screen where you select your user. Select your user name.
Step 4: Now, in the MS-DOS window like below, the directory will be C:\Users\(Your User Name)\ in Windows 7 and C:\Documents and Settings\(Your User Name)\ in Windows XP
Step 6: Type cd $Recycle.Bin in Win7 or cd RECYCLER in WinXP and press enter.
Step 7: Type cd and press tab. You'll see that the line is filled with a directory name like this "S-1-5-21-564594560-2944949298-4040108220-1000". Press enter.
Step 8: Type dir/a to see all the files including hidden files in that directory. The file you want to recover will also be there. But the name of the file may be changed.
Step 9: Here I deleted a system file named "BOOTSECT.BAK". Its been renamed as "$I1R8ZP3.BAK"
For eg., type copy $I1R8ZP3.BAK C:\
Step 11: Type cd../.. to go to the root directory.
Step 12: Type dir and enter. You'll see the file you copied from the Recycle Bin directory there.
For eg., type ren $I1R8ZP3.BAK BOOTSECT.BAK
Step 14: Thats it! The file is restored. Restart your computer and enjoy the Graphic UI of Windows again! :P