installing service pack 5 for Visual Basic 6 was problematic in windows 7. The installer checks the MDAC version and gives the warning that MDAC 2.5 should be installed as a minimum (I am sure a higher version of MDAC is installed in windows 7). After the warning it quits the setup procedure.
To get around this issue the following worked for me:
In the enu folder edit the following file: sp598ent.stf
From the following line remove the number 36:
Old line: 13 Group 28 36 38 29 30 32 26 27 14 25 16 17 20 18 19 15 39 21 22 24 23 43
New line: 13 Group 28 38 29 30 32 26 27 14 25 16 17 20 18 19 15 39 21 22 24 23 43
Delete the following 2 lines replacing them with just carriage returns:
36 Depend "27 ? : 37"
37 IsWin95 CustomAction "sp598ent.dll,CheckForMDAC"
Save the file and run the installer again.