You will need to download the following:
1. any XP iso. preferably SP3. (Download it yourself)
2.Microsoft virtual PC 2007. (Link given below)

Step 1:
Install Microsoft virtual PC 2007
LINK: http://www.4shared.com/file/161996257/4c656f8d/MS_Virtual_PC_2007.html

Step 2:
after installing make new virtual machine using the wizard (select windows XP on select OS screen).

step 3:
after making new virtual machine start the new virtual machine.

step 4:
now it will be on the black screen with some text written which goes like ..... Argon PXE boot agent v2.0and BLAH BLAH BLAH!

step 5:
now u need to click on the 'CD' option in the tool bar and select 'capture ISO image' option from the drop down menu.

step 6:
As soon as u do this a window will open in which u need to go to the XP SP3 iso select it and click on open...
.
now go to file>reset and your XP setup will start.

step 7:
complete XP setup and come to desktop of XP virtual PC.

step8:
now u need to go to Actions>Install or update virtual machine additions.
click ok on all the boxes which pop up.
let the software install on XP inside ur virtual PC.
it will ask u to restart ur XP(virtual). Do it.

step 9:
Now open 'Virtual PC console' which must have minimised into ur taskbar.

step 10:
in the console select the virtual Machine u just made and start it and let XP boot.

step 11:
once it boots go to console again and select ur virtual machine and click on settings.
in settings select 'shared folders' option.

now on right hand side click on 'share folder' and share the Turbo C folder present in ur real PC (Vista).

step 12:
now go to ur virtual PC (XP). and go to my computer.
there u will see ur Shared TC folder.
now copy the folder and paste it into C drive of ur virtual PC for quick access.

step 13:
now open Turbo C normally as u wud do in XP in ur college.

NOTE:
when u open TC the window will become small. dont worry just press ALT+ENTER and it will go to fullscreen mode.

HAPPY C PROGRAMMING!!!



Enjoy...