UDK 3 Build version issue

I have this issue where I am unable to work on my crappy map on UDK 3 for TAFE (Community Colleges, Go google the equivalent of TAFE to your country) and UDK keeps updating the build version making me unable to work on it since the version that TAFE has is an out of date one and when I try to install it with their installer and run UDK it updates automatically

Please help, cause I have been slacking a little during class time in tafe due to the computer lab that i am in is kinda weak for UDK. because my class is kinda big this year because we could not fit into the Alienware labs that they have.

Spec of computers at TAFE

i5 2500k
Radeon 6450.
8gms (i think)

they are all prebuilt dells.