I realise that in theory there are 26 being a letter of the alphabet assigned to each drive.
The practical side to this is I'm gonna grab another external drive in 05 and this time around I'm going to partition it so if it's a 160gb I'll probably go for 4 x 40gb, which will mean 4 drive letters. If I also partition my other drives I may end up with an additional 10 virtual drives occupying 10 more letters ontop of the existing a, c, d, e, f, and occassional g and h removable drives.
Am I likely to have configuration problems with so many drive letters, and what's the max no. of drive letters I'm allowed.
As said before, A & B reserved for floppy. C to Z available therefore a total of 24. BUT it is best to leave Z free in case you ever need to use a boot disk which creates a RAM drive, or plug in a removeable drive such as a USB pen drive so really 23. I have an OS on C to R, two data drives S & T plus two optical drives at U and V. The OS's I run are 95OSR2 (one), Win98SE (four), Win ME (one) XP pro (eight) and a couple of spares - All under HyperOs which is an OS multiplier.
If you want more you can put two OS's on a single partition and with a batch files to rename the windows directories, you can effectively double up.