You mean view files on a QNX paritition in Windows XP? TTBOMK you cannot, you’re better off putting the files on a FAT32 partition if you want files to be available on both OS’s (i assume you are dual booting).
Windows XP cannot read a QNX partition.
There are all kinds of boot manager you can use to choose which OS to use, GRUB, LILI, Partition Commander etc.
To uninstall QNX, just wipe out the partition.
The differences are really just down to the development tools, and even then it’s not much of a big deal, you’ve got the extensions to Eclipse, which are not available in a non-commercial QNX, but regular Eclipse is. And then you got qcc, the C compiler, which is disabled after 30-days on QNX 6.3, but you can keep on using gcc, so it’s not really a big thing.