What is the equivalent of sudo in Windows 7?

The runas command is the equivelent of sudo in windows 7.

runas [{/profile|/noprofile}] [/env] [/netonly] [/smartcard] [/showtrustlevels] [/trustlevel] /user:UserAccountName program

Run the following command to start a command shell as an administrator. EDIT: Or you could right click the command prompt and click Run As Administrator.

runas /noprofile /user:Administrator cmd

Runas is a pretty functional equivalent.

It's easiest to run CMD as administrator (or elevated, in the case of standalone desktop Windows), but there is the runas command as well.