Allan,

If Mark's suggstions don't help, then try posting on the Installshield newsgroup.. it's pretty good and usually gives a helpful response

News.installshield.com

>Earlier today I packaged a VFP 7 app but did not include one of the necessary merge modules. The installs on the two P.C.'s went smoothly (i.e. no error messages), but since I didn't include the merge module containing MSVCR70.dll - the apps obviously did not run.
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>So, I went back to InstallSheild, added the merge module, and re-built the CD.
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>Went back to the P.C. to run the setup and a messagebox appeared saying that...
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>"Another version of this product is already installed. Installation of this version cannot continue. To configure or remove the existing version of this product, use Add/Remove programs in the control panel."
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>OK - go into the control panel on both the P.C.'s that the 'wrong' install was done on and the app does not appear in the list of programs - so I can't remove it.
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>Interestingly, I did run the install on my development machine and the app does appear in Add/Remove programs - and I am able to remove it. However, that is not the case on the other two P.C.'s
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>Any idea as to what I will need to do to get the app installed - again?
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>AL