I have experienced any applications's setup.exe to run very, very slow under Win95, then Win98, and now most recently under Win2000. I just recently installed a new motherboard and processor - a celeron 400mhz, 128MB ram, 6GB IDE and 2 20GB SCSI HDDs, and a SCSI 2X CD-R.
Anytime I run setup off of a CD OR off of a hard drive, I see the initial status indicator go from 0% to 100% with exepcted speed and it then disappears and it will take 3 or 4 minutes before the actual installation program appears. Once the installation part of the programs appear, the rest of the installation goes as fast as I would normally expect.
I have been living with this for several years thinking I've just got a slow CD-R drive, but last week I installed a clean installation of Win2000 and began re-installing all of my apps. The first 3 or 4 flew at speeds that I would normally expect, but then all of a sudden, one of the apps took forever to run and from that point on, they have all been extremely slow.
So, because the first several apps installation quickly, that proved to me that it can't be the CD-R drive plus the fact that the same thing happens when I run setup off of the hard drive. Also, a new motherboard and CPU and memory made no difference.