Maybe you need to uninstal the old version first, Then install the new.
Wierd though, it should've updated to 7.80.

SED should be 7.21
MED should be 6.907
WED should be 7.80/6.93

Windows XP SP3
Intel Dual Core CPU: E5200 @ 2.5GHz
4.00GB DDR3 Ram
ASUS P5G41T-M LX
PCIE x16 GeForce GTS 450 1Gb
SB Audigy 4
Spyware Doctor with AntiVirus