If it's on the same disk (two partitions on one disk) then yes, it can be done easily. Open up computer management or disk management and just delete the second partition (make sure to back up your data on it) so that you get some free space, and use the extend feature:
Alternatively, if you can be bothered to read a bit, this is far more awesome and imo the easier way to do it (easier being relative - I hate messing with Windows' tools):
http://www.mpgh.net/forum/74-hardwar...artitions.html