I have been meaning to switch to Linux for a long, long time now. The first time that I attempted to do anything about it was about three years ago, when I obtained the Mandrake 8.2 installation CDs (I had to order them through the mail, as I was still on dialup). The installation went okay (apart from the fact that I got confused when partitioning the hard drive, and ended up leaving a megabyte of free space on the Windows partition instead of a gigabyte (or something like that)) but when I got to first boot, there were two deal-breakers.
It didn’t detect my modem, and it didn’t detect the soundcard built into the motherboard.
The absence of the latter wouldn’t have been a problem, but the fact that I couldn’t get onto the Internet meant that trying to fix these two problems seemed like an enormous undertaking.
Of course, when I realised that my Windows partition was now unusably crowded, I had to reformat the whole thing. This put me off of switching to Linux for a few years, and I decided to make do with Windows for a while. It’s not perfect, but at least it works (or appears to, at least).